Space Group Research Articles

Enumeration and Representation Theory of Spin Space Groups

Fundamental physical properties, such as phase transitions, electronic structures, and spin excitations, in all magnetic ordered materials, were ultimately believed to rely on the symmetry theory of magnetic space groups. Recently, it has come to light that a more comprehensive group, known as the spin space group (SSG), which combines separate spin and spatial operations, is necessary to fully characterize the geometry and underlying properties of magnetic ordered materials. However, the basic theory of SSG has seldom been developed. In this work, we present a systematic study of the enumeration and the representation theory of the SSG. Starting from the 230 crystallographic space groups and finite translation groups with a maximum order of eight, we establish an extensive collection of over 100 000 SSGs under a four-index nomenclature as well as international notation. We then identify inequivalent SSGs specifically applicable to collinear, coplanar, and noncoplanar magnetic configurations. To facilitate the identification of the SSG, we develop an online program that can determine the SSG symmetries of any magnetic ordered crystal. Moreover, we derive the irreducible corepresentations of the little group in momentum space within the SSG framework. Finally, we illustrate the SSG symmetries and physical effects beyond the framework of magnetic space groups through several representative material examples, including a candidate altermagnet RuO2, spiral spin polarization in the coplanar antiferromagnet CeAuAl3, and geometric Hall effect in the noncoplanar antiferromagnet CoNb3S6. Our work advances the field of group theory in describing magnetic ordered materials, opening up avenues for deeper comprehension and further exploration of emergent phenomena in magnetic materials. Published by the American Physical Society 2024

Lazerckerite, Ag3.75Pb4.5(Sb7.75Bi4)S24, from Kutná Hora, Czech Republic: a new Sb–Bi member of the andorite branch of the lillianite homologous series

Abstract. Lazerckerite, ideally Ag3.75Pb4.5(Sb7.75Bi4)S24, is a new mineral species found in medieval mine dumps of the historic Ag–Pb–Zn Kutná Hora ore district, Czech Republic. The mineral is associated with other Sb–Bi lillianite homologues (terrywallaceite, gustavite, holubite) and Ag,Bi-bearing galena, most frequently as grain aggregates and replacement rims of earlier Ag–Pb–Bi minerals, growing together in aggregates of up to 0.6×0.3 mm. Lazerckerite is opaque, is steel grey in colour, and has a metallic lustre; the calculated density is 5.920 g cm−3. In reflected light lazerckerite is greyish white, and bireflectance and pleochroism are weak with grey tints. Anisotropy is weak to moderate with grey to bluish-grey rotation tints. Internal reflections are not observed. Electron microprobe analyses yielded the empirical formula, based on 44 apfu, (Ag3.61Cu0.04)Σ3.65(Pb4.55Fe0.01Cd0.01)Σ4.57(Sb7.87Bi3.75)Σ11.62(S24.15Se0.01)Σ24.16. Its unit cell parameters are a=13.2083(9), b=19.4595(8), c=8.4048(13), β=90.032(7)°, V=2160.3(4) Å3, space group P21/c, and Z=2. The structure of lazerckerite contains two Pb sites (Pb1 and Pb2) in bicapped trigonal prismatic coordination, 8 independent octahedral sites, and 13 distinct sulfur positions. Four of the octahedral sites are mixed (Sb,Bi) and (Bi,Sb) sites, one is a mixed (Ag,Bi) site, and one is a mixed (Sb,Pb) site. The new mineral belongs to the andorite branch of the lillianite homologous series with N=4 and is a new addition to the group of Sb–Bi mixed members of the series. Lazerckerite is defined as a lillianite homologue with the three following requirements: N=4, L (Ag++ (Bi3+, Sb3+) ↔ 2 Pb2+ substitution) ≈ 90 %–95 %, and approximately one-third of atom percentage of antimony is replaced by bismuth (Bi/(Bi+Sb) ≈ 0.30–0.38). The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA 2022-113) and named after Lazarus Ercker, the supreme Royal Bergmeister of the Kingdom of Bohemia and the Master of Prague Mint.

Spin Space Groups: Full Classification and Applications

In this work, we exhaust all the spin space symmetries, which fully characterize collinear, noncollinear, and commensurate spiral as well as incommensurate spiral magnetism, etc., and investigate enriched features of electronic bands that respect these symmetries. We achieve this by systematically classifying the so-called spin space groups (SSGs)—joint symmetry groups of spatial and spin operations that leave the magnetic structure unchanged. Generally speaking, they are accurate (approximate) symmetries in systems where spin-orbit coupling (SOC) is negligible (finite but weaker than the energy scale of interest), but we also show that specific SSGs could remain valid even in the presence of strong SOC. In recent years, SSGs have played increasingly pivotal roles in various fields such as altermagnetism, topological electronic states, and topological magnon, etc. However, due to its complexity, a complete SSG classification has not been completed up to now. By representing the SSGs as O(N) representations, we—for the first time—obtain the complete classifications of 1421, 9542, and 56 512 distinct SSGs for collinear (N=1), coplanar (N=2), and noncoplanar (N=3) magnetism, respectively. SSG not only fully characterizes the symmetry of spin degrees of freedom, but also gives rise to exotic electronic states, which, in general, form projective representations of magnetic space groups (MSGs). Surprisingly, electronic bands in SSGs exhibit features never seen in MSGs, such as (i) nonsymmorphic SSG Brillouin zone, where SSG operations behave as a glide or screw when acting on momentum, (ii) effective π flux, where translation operators anticommute with each other and yield duplicate bands, (iii) higher-dimensional representations unexplained by MSGs, and (iv) unconventional spin texture on a Fermi surface, which is completely determined by SSGs, independent of Hamiltonian details. To apply our theory, we identify the SSG for each of the 1595 published magnetic structures in the MAGNDATA database on the Bilbao Crystallographic Server. Material examples exhibiting the novel features (i)–(iv) are discussed with emphasis. We also investigate new types of SSG-protected topological electronic states that are unprecedented in MSGs. In particular, we propose a 3D Z2 topological insulator state with a fourfold degenerate Dirac point on the surface and a new scenario of anomalous Z2 helical states that appear on magnetic domain walls. Published by the American Physical Society 2024

Enumeration of Spin-Space Groups: Toward a Complete Description of Symmetries of Magnetic Orders

Symmetries of three-dimensional periodic scalar fields are described by 230 space groups (SGs). Symmetries of three-dimensional periodic (pseudo)vector fields, however, are described by the spin-space groups (SSGs), which were initially used to describe the symmetries of magnetic orders. In SSGs, the real-space and spin degrees of freedom are unlocked in the sense that an operation could have different spatial and spin rotations. SSGs give a complete symmetry description of magnetic structures and have natural applications in the band theory of itinerary electrons in magnetically ordered systems with weak spin-orbit coupling. , a concept raised recently that belongs to the symmetry-compensated collinear magnetic orders but has nonrelativistic spin plitting, is well described by SSGs. Because of the vast number and complicated group structures, SSGs have not yet been systematically enumerated. In this work, we exhaust SSGs based on the invariant subgroups of SGs, with spin operations constructed from three-dimensional (3D) real representations of the quotient groups for the invariant subgroups. For collinear and coplanar magnetic orders, the spin operations can be reduced into lower-dimensional real representations. As the number of SSGs is infinite, we consider only SSGs that describe magnetic unit cells up to 12 times crystal unit cells. We obtain 157 289 noncoplanar, 24 788 coplanar-noncollinear, and 1421 collinear SSGs. The enumerated SSGs are stored in an online database with a user-friendly interface. We develop an algorithm to identify SSGs for realistic materials and find SSGs for 1626 magnetic materials. We also discuss several potential applications of SSGs, including the representation theory, topological states protected by SSGs, structures of spin textures, and refinement of magnetic neutron diffraction patterns using SSGs. Our results serve as a solid starting point for further studies of symmetry and topology in magnetically ordered materials. Published by the American Physical Society 2024

A New Azide-Bridged Polymeric Manganese (III) Schiff Base Complex with an Allylamine-Derived Ligand: Structural Characterization and Activity Spectra

This paper reports the synthesis and structural characterization of a novel azide-bridged polymeric manganese (III) Schiff base complex, using 2-((allylimino)methyl)-6-ethoxyphenol as a ligand. The crystal structure of the synthesized compound, elucidated by single-crystal X-ray diffraction analysis, indicates that it crystallizes in the monoclinic space group P21/c. The complex is found to display an octahedral geometry in which the central manganese Mn(III) coordinates with two bidentate donor Schiff base ligands via oxygen and nitrogen atoms. In addition, the metallic centers are linked together to form a one-dimensional chain bridged by end-to-end azide ligands. To offer a more thorough characterization of the synthesized compound, the study incorporates experimental data from FT-IR, UV-Vis, and cyclic voltammetry, alongside computational results from Hirshfeld surface analysis and DFT calculations conducted for both the ligand and complex. The computational analyses provided valuable insights into the intrachain and interchain interactions within the crystal structure, clarified the conformational characteristics of the isolated ligand molecule, and aided in the interpretation of the experimental IR spectra. Furthermore, an assessment of the compound’s drug-like properties was conducted using activity spectra for substances (PASS) predictions, revealing potential pharmacological activities.

Design, structure and antivirus molecular docking of chloridobis(1,10-phenanthroline)-(thiocyanato)-copper(II)

The reaction of sodium thiocyanate with CuCl2·2H2O salt using 1,10-phenanthtroline as a co-ligand led to chloridobis(1,10-phenanthroline)-(thiocyanato) copper(II), [Cu(Phen)2(Cl)(NCS)] (1). The structure of 1 was characterized by single crystal X-ray crystallography, UV-Visible and fluorescence spectroscopy. 1 crystallized in the monoclinic crystal system with space group P21/n and revealed a distorted octahedral coordination geometry. Electronic properties such as HOMO and LUMO energies were derived through DFT calculations. Hirshfeld surface analysis and 2D fingerprint plot was used to analyze the intermolecular interactions within the crystal structure. To develop anti-SARS-CoV-2 and anti-HIV drugs, we performed molecular docking studies for antiviral activity against the main protease (Mpro) of the SARS-CoV-2 (PDB ID: 6LU7 and 7LKD) and HIV-1 protease (PDB ID: 8FUI) viruses. The molecular docking calculations reveal that 1 with the Mpro of SARS-CoV-2 virus and HIV-1 protease virus resulted in calculated binding energies (ΔG) of −7.6, −7.5 and −7.2 kcal/mol with inhibition constant/dissociation constant (Ki/Kd ) values of 4.567, 4.432 and 4.632 µM, respectively. The in-vitro antibacterial study was conducted to check the efficacy of 1 against some selected bacteria. Further, the in-silico antiviral efficacy analysis shows the potential of this complex as an antiviral drug. 1 may be used as anti-SARS-CoV-2 and anti-HIV-1 agents.

Microstructural and Magnetic Characteristics of Nanocrystalline Sm4ZrFe33 Alloys

This work focuses on the study of the microstructure and magnetic properties of nanocrystalline powders of Sm4ZrFe33, prepared by high‐energy ball milling. The Sm4ZrFe33 compound adopts a monoclinic structure (space group Cm). Upon annealing, these Sm4ZrFe33 samples exhibit notable variations in their extrinsic magnetic properties, closely linked to temperature fluctuations. The investigation delves into the correlation between morphology, grain size and magnetic characteristics. A significant enhancement in coercivity (Hc), remanent magnetization (Mr), and maximum energy product ((BH)max) is observed, primarily attributed to the finer grain structure present in the samples. Particularly noteworthy, among all annealed specimens, the nanocrystalline Sm4ZrFe33 compound annealed at a temperature of Ta = 973 K demonstrates the most promising magnetic properties. This specimen exhibits a coercivity Hc of 18 500 Oe, remanent magnetization (Mr) of 58 emu g−1, maximum energy product ((BH)max) of 5.18 MGOe, Curie temperature (TC) of ≈804 K, and magnetic anisotropy field (Ha) of 115 980 Oe. These research findings pave the way for future investigations and applications in the realm of permanent magnets, spintronic devices, and magnetic recording, utilizing nanocrystalline alloys based on the Sm4ZrFe33 compound.

Layered sodium manganese oxides for toxic nitrogen dioxide gas removal in ambient conditions

In this study, Na0.7MnO2 samples were successfully synthesized using a solid-state synthesis route with Na and Mn acetate precursors. The resulting Na0.7MnO2 crystallized in a hexagonal lattice with space group P63/mmc. These materials were investigated for their capacity to adsorb 100 ppm of NO2 gas at room temperature. Na0.7MnO2 exhibited an exceptional NO2 adsorption capacity of 163.3 mg/g, surpassing many previously reported porous and non-porous materials. Comprehensive experimental and spectroscopic analyses confirmed the formation of NO, NO2–, and NO3– species, following NO2 adsorption on the Na0.7MnO2 surface. Theoretical calculations further supported the chemisorption of NO2 gas molecules on the Na0.7MnO2 surface, with a maximum adsorption energy of –1.937 eV. Spectroscopic and Bader charge analyses confirmed that the NO2 gas molecule acted as a charge acceptor species on the oxide surface. This work represents the first detailed study validating Na0.7MnO2 as an effective room-temperature adsorbent for capturing and mineralizing NO2 gas. The exceptional NO2 adsorption capacity and the mechanistic insights into the adsorption process suggest the promising potential of Na0.7MnO2 and related oxides for applications in NO2 gas capture and conversion.

Molecular drug design, theoretical, experimental approaches and new framework of novel oxazol dihydroquinoxaline (ODQ): Efficient synthesis, crystallographic, computational investigation, DFT calculation, ADME analysis and antiangiogenic molecular docking

Drug design, also known as rational drug design, is a methodical procedure that seeks to discover and develop novel chemicals with therapeutic potential. The process entails the identification and modification of molecular structures that can efficiently interact with biological targets in order to achieve a desired therapeutic effect. The title compound, 1-([3-(4-chlorophenyl)-4,5-dihydro-1,2-oxazol-5-yl]methyl)-3-phenyl-1,2-dihydroquinoxalin-2-one ODQ (c), was synthesized with good yield by adding the solution of 1-allyl-3-phenylquinoxalin-2(1H)-one and 4-chlorobenzaldehyde oxime in dichloromethane. This mixture was then mixed with an excess of aqueous sodium hypochlorite solution while stirring at 0–5 °C. The resulting mixture was dried to obtain a crude product. The structure of the compound was confirmed by NMR and LC-MS spectra. The single-crystal X-ray studies conform to the 3D structure of the molecule. The molecule crystallizes in the triclinic system with the space group P-1. Hirshfeld surface analysis confirms the intermolecular interactions of the type CH…O and CH…N contacts. DFT calculations were performed to determine the electronic properties of the molecule. MEP analysis predicts the chemical reactive sites around oxygen and nitrogen atoms. This investigation has provided valuable insights that could drive significant advancements in molecular science and drug design. Additionally, the molecular docking studies elucidated the compound's interactions with various biological targets. The notable binding affinities observed for these targets highlight the potential therapeutic relevance of the synthesized compound across a range of disease conditions.

Growth of Single Crystals of (K1-xNax)NbO3 by the Self-Flux Method and Characterization of Their Phase Transitions.

In this study, single crystals of (K1-xNax)NbO3 are grown by the self-flux crystal growth method and their phase transitions are studied using a combination of Raman scattering and impedance spectroscopy. X-ray diffraction shows that single crystals have a perovskite structure with monoclinic symmetry. Single crystal X-ray diffraction shows that single crystals have monoclinic symmetry at room temperature with space group P1211. Electron probe microanalysis shows that single crystals are Na-rich and A-site deficient. Temperature-controlled Raman scattering shows that low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions take place at -20 °C, 220 °C and 440 °C. Dielectric property measurements show that single crystals behave as a normal ferroelectric material. Relative or inverse relative permittivity peaks at ~-10 °C, ~230 °C and ~450 °C with hysteresis correspond to the low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions, respectively, consistent with the Raman scattering results. A conduction mechanism with activation energies of about 0.5-0.7 eV was found in the paraelectric phase. Single crystals show polarization-electric field hysteresis loops of a lossy normal ferroelectric. The combination of Raman scattering and impedance spectroscopy is effective in determining the phase transition temperatures of (K1-xNax)NbO3.

Synthesis, crystal structure, Hirshfeld surface analysis, DFT studies and biological evaluation of bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate

The complex bis(acetonitrile)bromido(η6-1-isopropyl-4-methylbenzene)osmium(II) hexafluoroantimonate, [OsBr(C10H14)(CH3CN)2]SbF6 (1) crystallizes as a triclinic system in space group P1 (no. 2), consisting of two cationic osmium(II) complex ions and two anionic hexafluoroantimonate counterions in each cell. Density Functional Theory (DFT) calculations were performed at the B3LYP/LanL2DZ and B3LYP/Def2 − SVP/Def2 − TZVP levels of theory. Reactivity descriptors and charge transfer properties were computed using frontier molecular orbital analysis. The DFT-optimized model systems from both basis sets were comparable to the experimentally determined X-ray diffraction results. Hirshfeld surface analysis shows significant non-covalent interactions including hydrogen bonds and halogen interactions. The MTT technique was utilized to conduct an in vitro cytotoxicity assay of 1 against cancerous cell lines (MCF-7 and A549) and normal cells (HEK293). Complex 1 is potent towards cancer cells as evidenced by the IC50 values of 5.02 ± 0.05 µM for MCF-7 cells and 13.36 ± 0.04 µM for A549 cells. Complex 1 demonstrated lower toxicity to normal cells with an IC50 value of 26.76 ± 0.08 µM for the HEK293 cell line compared to the doxorubicin standard with an IC50 value of 1.2 ± 0.1 µM.

Low-temperature synthesis and luminescence properties of blue-emitting β-SiAlON:Eu2+ phosphor using melamine as a self-propagating raw material

Sialons are widely recognized for their rigid lattice structure, high visible light transmittance, and excellent thermal stability, making them suitable matrix materials for activators. In this paper, we successfully prepared β-sialon phosphors, β-Si6-zAlzOzN8-z:Eu2+ (β-SiAlON:Eu2+), using an organic precursor method at a low synthesis temperature for the first time. X-ray diffraction analysis and Rietveld refinement confirm the β-SiAlON:Eu2+ phosphor possesses a hexagonal structure with a P63 space group. Under 320 nm excitation, β-SiAlON:Eu2+ phosphor exhibits a blue emission band centered at 415 nm due to the 5d → 4 f electron transition of Eu2+, which differs significantly from other β-SiAlON:Eu2+ phosphors with green emission. It is interesting that excessive Eu2+ activators make β-SiAlON:Eu2+ phosphor possess a green emission band centered at 510 nm. Therefore, the light-emitting color of β-SiAlON:Eu2+ phosphor shifts from the blue to the green with the increase of Eu2+ concentration. Furthermore, the activation energy of β-SiAlON:0.02Eu2+ sample is calculated to be about 0.2527 eV, which confirms β-SiAlON:Eu2+ phosphor has good thermal stability. The article presents a low-temperature and cost-effective synthesis method for preparing sialons, as well as a novel blue β-SiAlON phosphor for solid-state lighting.

Copper (II) halide compounds with cationic N-donor ligands: Design, synthesis, structure and magnetism

Copper (II) complexes of the cationic ligands 1-(4′-pyridyl)-pyridinium (L1) and 1-(4′-pyridyl)-pyridin-4-ol (L2) have been prepared and characterized by single crystal X-ray diffraction and variable temperature magnetic susceptibility measurements: [Cu(L1)2X2]X2 [where X = Cl (1), Br (2)], and [Cu(L2)2X2]X2 [where X = Cl (3), Br (4)]. The complexes are fundamentally square planar with L2X2 coordination planes and long, semi-coordinate bonds to the additional halide ions. All compounds crystallize in monoclinic systems with 1 and 2 in the P21/n space group and 3 and 4 in the P21/c space group. The crystal structures are stabilized by both non-classical (in the case of 1 and 2) and classical (3 and 4) hydrogen bonds. EPR data for 1–4 support a rhombohedral structure, in good agreement with the local geometry as seen in the crystal structures. Magnetic susceptibility measurements show the presence of very weak antiferromagnetic interactions. In addition, the syntheses and magnetic properties of two neutral complexes, [Cu(L3)2X2]·2H2O [L3 = 1-(4′-pyridino)-4-pyridone; X = Cl (5), Br (6)] are reported. Magnetic susceptibility data indicate the presence of moderate antiferromagnetic exchange interactions [J ∼ 28 K (5), 60 K (6)] which were well modeled by the S = 1/2 Heisenberg uniform chain model.

Effects of doping with magnetic cations on the hybrid improper ferroelectricity in Sr3Sn2O7

We here report the structural, magnetic and electrical properties of Sr2.9La0.1Sn1.9M0.1O7 (M= Cr, Mn or Fe) compounds. This La/M codoping of the hybrid improper ferroelectric Sr3Sn2O7, allows introducing magnetic cations into the perovskite layers of this Ruddlesden-Popper phase. The doping induces minor structural changes, preserving the polar structure with space group A21am of the undoped compound. The perovskite tolerance factor of all doped samples is slightly lower than in Sr3Sn2O7, which preserves the tilts and rotations of SnO6 octahedra. Doped samples exhibit a paramagnetic behavior down to 5 K and obey the Curie-Weiss law above 200 K. The effective paramagnetic moments agree with the expected spin-only values of the respective magnetic M3+ cations. All samples show a ferroelectric hysteresis loop at room temperature, but the doped samples show larger coercive fields. Additionally, the doping with magnetic cations has important effects on the dielectric properties: a strong decrease of the temperature of the ferroelectric transition together with a smoothing of the anomaly in the dielectric permittivity. These results suggest that the disorder produced by the two aliovalent substitutions is detrimental for the ferroelectric properties due to point charge defects but, at the same time, the prevalence of the structural distortion (tilts and rotations) preserves the ferroelectricity in the investigated doping regime.

Green synthesis of calcium nanoferrites using leaf extract of Brassica oleracea for photocatalysis of malachite green dye

The calcium ferrite nanoparticles were made by the sol–gel process. X-ray diffraction, a scanning electron microscope, and UV–vis spectroscopy were used to analyze the material. There is an orthorhombic phase in the space group Pnma. There were four techniques used to calculate the average crystallite size. Using ImageJ software, the particles were aggregated and their size was ascertained. Using energy-dispersive X-ray (EDX) analysis, the composition of the material was ascertained. 2.29 eV was determined to be the band gap. Vibrating test magnetometer (VSM) provided an explanation for the materials’ magnetic property. A decreased band gap energy is responsible for the 90% degradation of malachite green dye at a concentration of 15 mg/L in 150 min, with a four-cycle reusability.

Structure and properties analysis of yttrium doped high-voltage LiNi0.5Mn1.5O4 cathode materials for Li-ion batteries

High voltage cathode spinel material of LiNi0.5Mn1.5O4 was doped by yttrium (Y) element in the form of LiNi0.5Mn1.5−x Y x O4 (x = 0, 0.05, 0.1) for Li-ion batteries. Structure and properties analysis was conducted to study the effect of Y addition on the crystal structure and the electrochemical performances of LiNi0.5Mn1.5−x Y x O4. The results show that undoped LiNi0.5-Mn1.5O4 (x = 0) fit to cubic spinel structure with space group Fd-3m with some LixNi1-xO detected as impurities. The addition of Y with x = 0.05 and 0.1 resulted in the change of LiNi0.5Mn1.5−x Y x O4 structure to space group P4 332. The Y addition was confirmed to enter 4b site co-existed with Mn and this result is closely related to the increase in lattice parameters a from 8.1384(1) Å to 8.1496(5) Å and 8.1627(1) for x = 0, 0.05 and 0.1, respectively. The cubic unit volume of LiNi0.5Mn1.5−x Y x O4 also increased with increasing Y addition. The addition of Y is liable to the formation of more stable [Mn,Y]O6 and MnO6 octahedra and whole crystal structure. The result from charge/discharge analysis shows that the addition of Y resulted in decreasing discharge capacity from 123.56 mAh g−1 to 105.175 mAh g−1 and 104.369 for x = 0.05 and 0.1, respectively. However, capacity retention after the 25th cycle increased constantly from 77% to 88% and 92% with increasing Y addition. Doped Y, in general, improves the electrochemical performance of LiNi0.5Mn1.5−x Y x O4 as cathode material for LIBs.

Investigations on structural, morphological and UV light detection characteristics in p- ZrO2/ n-Si Heterostructure based devices

The development of hetero-structured based UV photodiode is a rapidly growing interest in the area of optoelectronic applications. In recent years, one of the next generation semiconductor material zirconium dioxide (ZrO2), has attracted much attention for UV photodiode applications. The curent research work focuses on the fabrication of ultraviolet (UV) photodetectors using ZrO2 nanocrystals with different molar concentrations. Using the co-precipitation method, ZrO2 nanocrystals were formed onto n-Si substrate. The prepared ZrO2 nanocrystals were characterized by XRD, UV–visible spectroscopy, FeSEM, HRTEM, PL spectroscopic analysis. The structural analysis of ZrO2 nanoparticles shows the cubic space groups with ((Fm-3m, Z = 4) and (Im-3m, Z = 1) respectively. The morphological analysis reveals the irregular shape and highly agglomerated. The TEM and HR-TEM images, and SAED pattern of ZrO2 NPs were obtained at higher mole concentration. The optical energy band gap of ZrO2 nanocrystals were determined in between 3.12 and 2.86 eV. The PL emission spectrum of ZrO2 nanoparticles shows highly intensive emission bands between 360 nm and 520 nm. The optimum ZrO2 (0.3 M) nanocrystal layers were formed onto n-Si substrate which was stacked between top and bottom Ag electrodes. The current-voltage measurements (I–V) plots and ln J-V plots characteristics of the fabricated Ag/p-ZrO2/n-Si/Ag devices were investigated under dark and UV illumination. The p-ZrO2/n-Si junction diodes exhibit the ideal rectifying function at higher molar concentration of ZrO2 diode, and the reverse saturation with maximum photo sensitivity was investigated.

Structural and computational analysis of a nickel(II) complex with S-benzyldithiocarbazate Schiff base ligand: Synthesis, X-ray crystallography, MEP, HOMO-LUMO, Hirshfeld surface analysis, and molecular docking

A new compound, benzyl N-[1-(thiophen-2-yl)propylidene]hydrazinecarbodithioate (LH), and its nickel(II) complex (NiL2), were synthesized and structurally identified. Single crystal X-ray diffraction analyses determined that both the LH ligand and the NiL2 complex crystallized in the monoclinic system, with space group P21/c and Z = 4. The LH ligand exhibited lattice parameters of a = 9.661(2)Å, b = 8.995(2)Å, c = 18.939(4)Å, β = 102.677(4)°, V = 1605.7(7)Å3, whereas, NiL2 exhibited a = 17.805(7)Å, b = 10.548(4)Å, c = 18.100(7)Å, β = 108.279(6)°, V = 3228(2)Å3. The NiL2 complex was found to possess a slightly distorted square planar geometry with the LH deprotonated ligand acting as a monoanionic bidentate by coordinating through the azomethine nitrogen and thiolate sulfur atoms. It was observed that the HOMO-LUMO energy gap of the NiL2 complex (0.3654 eV) was lower than that of the LH ligand (2.4425 eV), indicating that NiL2 possesses a higher reactivity than the LH ligand. Intermolecular hydrogen bonding interactions were examined by Hirshfeld surface and 2D fingerprint analysis, which showed predominant H…H interactions for both the LH ligand and the NiL2 complex. A molecular docking simulation study with the dopamine D4 receptor (DRD4) and farnesyltransferase (FTase) revealed that NiL2 was able to interact with 13 residues in FTase, as compared to the farnesyl-Cys drug interacted with 11 residues.

Chiral Ca–Mn-frameworks with double helical chains and one-dimensional channels constructed from enantiomorphous lactate synthons

Under solvothermal synthetic condition, lactate derivatives (R)-5-(1- carboxyethoxy)isophthalic acid ((R)-H3CIA) and (S)-5-(1-carboxyethoxy)isophthalic acid ((S)–H3CIA) assembled with Ca(Ⅱ) and Mn(Ⅱ) ions to obtain enantiomers {[MnCa0.5((R)-CIA)(H2O)]·((CH3)2NH2CH3CO2)0.5(H2O)}n (HU21-R) and {[MnCa0.5((S)-CIA)(H2O)]·((CH3)2NH2CH3CO2)0.5(H2O)}n (HU21–S), respectively. Complexes HU21-R and HU21–S belong to orthorhombic crystal system with chiral space group I212121. Single crystal X-ray diffraction analysis revealed that all oxygen atoms of synthons (R)-CIA3- and (S)-CIA3- participated in the coordination with metal ions. Thus, semi-rigid (R)-CIA3- and (S)-CIA3- anions become rigid linkers in HU21-R and HU21–S. Fragments of (R)-CIA3- anion are connected by Ca(Ⅱ) ions to build right-handed double helical chains in HU21-R, while the enantiomeric left-handed double helixes are constructed by (S)-CIA3- fragments and Ca(Ⅱ) ions in HU21–S. Additionally, Mn(Ⅱ) centers and CIA3− anions resulted in a rare 4,4,4-connected net with point symbol of (42.62.82)3(42.64). Ca(Ⅱ) ions were further filed into Mn-CIA-framework to form a three dimensional structure with one dimensional channel. Moreover, magnetic test indicates that the framework has a canted antiferromagnetic behavior.

Tailoring magnetic properties of novel (La0.25Nd0.25Sm0.25Gd0.25)1-xHoxMnO3 high-entropy perovskite ceramics by Ho doping

High-entropy perovskite ceramics (HEPCs) with equal atomic ratios have recently emerged as a highly promising class of materials due to their unique magnetic properties. However, the crystal structure, microstructure and magnetic properties of unequal atomic ratios HEPCs have yet to be fully investigated. In this paper, single-phase HEPCs (La0.25Nd0.25Sm0.25Gd0.25)1-xHoxMnO3 ((LNSG)1-xHxMO) have been synthesized using solid-state reactions. The effect of Ho element content (x = 0.25, 0.3, 0.35 and 0.4) on the structure and magnetic properties was systematically investigated. All samples exhibit an orthorhombic perovskite structure with a Pbnm space group and show obvious crystallization characteristics after sintering at 1250 °C for 16 h (LNSG)1-xHxMO HEPCs display a smooth surface texture and distinct grain boundaries, as well as significant hysteresis effects at T = 5 K. The spin-orbit interaction and magnetic anisotropy between Ho and Mn ions increase with the increase of Ho content, which increases the saturation magnetization (Ms) of HEPCs. (LNSG)0.6H0.4MO exhibits the lowest magnetic hysteresis losses among the considered samples, attributed to its highest Ms (50.95 emu/g) and the lowest coercivity Hc (0.6 kOe). These characteristics endow it with a potential application in magnetic storage devices.