Electronic Charge Density Research Articles

Investigating the electronic properties and reactivity of polyaniline emeraldine base functionalized with metal oxides

Due to its appealing qualities, such as its miniature size and the ability to modify physical properties through chemical synthesis and molecular design, polymer material offers considerable advantages over traditional inorganic material-based electronics. Conjugate polymers are particularly interesting because of their molecular design capabilities, which enable the synthesis of conducting polymers with a variety of ionization potentials and electron affinities (EA), and their ability to control the energy gap and electronegativity (χ). Accordingly, density functional theory (DFT) at the B3LYP/SDD model was used to present possible interactions between polyaniline (PANi) and both alkali and heavy metal oxides. Total dipole moment (TDM), HOMO–LUMO band gap energy (ΔE), ionization energy (IE), EA, chemical hardness (η), chemical potential (μ), electrophilicity index (ω), chemical softness (S), and χ are calculated. TDM of PANi increased while ΔE decreased due to functionalization. The distribution of electronic charge density in molecular electrostatic potential (MESP) maps together with the results of ω reflected the electrophilic nature. The obtained results confirmed that the addition of metal oxides significantly improves the TDM, ΔE, and reactivity descriptors. A strong correlation between the experimental and calculated IR spectra was observed. Additionally, PANi–2MgO and PANi–2MnO model molecules exhibited the highest reactivity. Accordingly, PANi functionalized with MgO and MnO are promising candidates for energy storage devices.

Principles-based investigation of lithium-based halide perovskite X2LiAlH6 (X=K, Mn) for hydrogen storage, optoelectronic, and radiation shielding applications

Scientists devote their time and energy to studying and developing hydrogen storage devices to address the energy crisis and climate change. Because of this, investigations are conducted to reveal the optoelectronic, structural, bader charge, electronic charge density, and hydrogen storage properties of X2LiAlH6 (X = K, Mn) within the framework of density functional theory, and calculations of the structural characteristics were carried out utilizing local and nonlocal, and hybrid functionals. An additional onsite Coulomb parameter (GGA + U), which includes the Hubbard parameter, was used to apply the potential. Calculations based on the Kramer-Kroning principle were used to determine the dielectric function, refractive index, extinction coefficient, and energy loss function. The results indicate that K2LiAlH6 and Mn2LiAlH6 are highly suitable for hydrogen storage applications. The gravimetric ratios of hydrogen storage capacities for both investigated materials are 5.2 wt %, and 7.5 wt %, respectively. The interaction of the Mn-d, Li-s, K-s, and H-s/p orbitals was the cause of hybridization, according to the optoelectronic characteristics. Compound stability is indicated by the negative computed formation energy of the materials under investigation. The electronic charge density analysis showed a mixed-bond semiconductor with low ionicity and high covalence. In addition, the radiation shielding properties of Mn2LiAlH6 and K2LiAlH6 were investigated using Phy-X software, showing promising results in linear attenuation, half-value layer, and mean free path, particularly for Mn2LiAlH6 due to its higher atomic number. This groundbreaking study represents a pioneering computational exploration of X2LiAlH6, offering promising advancements for future research in hydrogen storage applications.

A DFT-based computational study on a highly and lead-free inorganic new fluoroperovskite of Mg3PF3

Inorganic fluoroperovskite materials are increasingly important in solar technology due to their exceptional structural, optical, electronic, and mechanical properties. This study uses DFT calculations to investigate the properties of Mg3PF3 fluoroperovskite. Our results show a crystal structure and lattice parameter of (a = 4.64 Å) which align with previous theoretical and experimental findings, confirming the accuracy of our calculations. Mechanical analysis reveals that Mg3PF3 is naturally ductile, elastically anisotropic, and stable according to established criteria. The band structure and PDOS indicate that it is a semiconductor with direct bandgap of 3.88 eV at the Γ point, making it suitable for electronic applications. Electron charge density mapping suggests a predominantly ionic bonding nature. Optical property analysis shows significant dielectric constant peaks in the photon energy range favorable for solar cells. Overall, these findings position Mg3PF3 as a promising candidate for solar cell technology, highlighting its potential for enhancing renewable energy solutions.

First principles investigations of linear and nonlinear optical, radiation shielding and thermoelectric properties of the non-centrosymmetric Ba-based chalcogenides Ba2In2X5 (X=S, Te)

We explore the structural, elastic, optoelectronic, Radiation Shielding, and thermoelectric properties of Ba2In2X5 (X = S, Te) using first-principles computations and semi-classical Boltzmann Transport equations. These materials are classified as semiconductors exhibiting band gaps of 2.0 eV and 3.0 eV for both investigated NLO compounds that have more significant direct band gaps of superior optical birefringence and second-order NLO coefficients. The bonding properties have been investigated by analyzing the electron charge density (ECD) contour of the (1 0 1) crystallographic plane. It is clear from the reflectivity spectra that both compounds have a high degree of reflectivity, which could make them useful as UV and visible light shields. From 0 to 14.0 eV, the approximated reflectivity values, R (ω), are displayed against the incident photon energy. Therefore, the reflectivity is around 30 % before E ≈ 12.0 eV and 40 % reflection at ∼13.0 eV. Phase matching is possible for both compounds detected, as shown by the birefringence computations. Furthermore, the radiation shielding properties of Ba2In2S5 and Ba2In2Te5 have been evaluated using Phy-X software, demonstrating their potential effectiveness in medical and nuclear energy applications. The thermoelectric properties display N-type nature at low temperatures when the Seebeck coefficient changes from N to P-type at higher temperature ranges. These compounds have remarkable optical and thermal properties, rendering them highly attractive materials for thermoelectric and optoelectronic devices.

Atomic-scale imaging of laser-driven electron dynamics in solids

Resolving laser-driven electron dynamics on their natural time and length scales is essential for understanding and controlling light-induced phenomena. Capabilities to reveal these dynamics are limited by challenges in interpreting wave mixing of a driving and a probe pulse, low energy resolution at ultrashort time scales and a lack of atomic-scale resolution by standard spectroscopic techniques. Here, we demonstrate how ultrafast x-ray diffraction can access fundamental information on laser-driven electronic motion in solids. We propose a method based on subcycle-resolved x-ray-optical wave mixing that allows for a straightforward reconstruction of key properties of strong-field-induced electron dynamics with atomic spatial resolution. Namely, this technique provides both phases and amplitudes of the spatial Fourier transform of optically-induced charge distributions, their temporal behavior, and the direction of the instantaneous microscopic optically-induced electron current flow. It captures the rich microscopic structures and symmetry features of laser-driven electronic charge and current density distributions.

Single crystal structure features, optimization of ultrasonic conditions, density functional theory studies, and antibacterial activity of a new organic compound

The synthesis of a novel water-soluble organic compound, N’-acetyl-4-nitrobenzohydrazide, was successfully achieved using hydrothermal and sonochemical methods. The resulting products, denoted as 1 and 2, were obtained as single crystals and powder, respectively. Characterization of the crystals through single-crystal X-ray diffraction (SC-XRD) indicated a monoclinic system with space group -P 2yn. Elemental analysis (CHN), energy-dispersive X-ray spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA/DTA), and powder X-ray diffraction pattern (PXRD), were utilized to analyze the molecular structure of 1 and 2, confirming their identical nature. Furthermore, scanning electron microscopy (SEM) was employed to examine the surface morphology of compounds 1 and 2, revealing distinct morphological features and varying particle dimensions. The impact of time, temperature, and ultrasonic energy was examined to optimize the morphology and particle size of compound 2. A density functional theory (DFT) study was performed to find the role of intramolecular hydrogen bond (IHB) interactions on the capability of the different tautomers of newly synthesized organic compounds. Various properties such as total energies of tautomers, energies of the most important molecular orbitals, electronegativity, thermodynamic functions, molecular electrostatic potential (MEP) maps, electron charge densities, and aromaticity were computed. The antimicrobial activity of 1, and 2 have been evaluated against one Gram-positive (Staphylococcus aureus, ATCC 25923) and one Gram-negative (Escherichia coli, ATCC 25922) using the disc diffusion method. The analysis of the inhibition zones revealed that 2 exhibit enhanced antibacterial efficacy compared to 1. This observation suggests that particle size reduction may contribute to increased antibacterial activity, potentially due to enhanced interaction with bacterial targets.

The effects of crystal orientation and common coal impurities on electronic conductivity in copper–carbon composites

The electronic conduction properties of copper–graphene composite materials including common coal impurities are studied. Exploring the transport properties for three crystallographic orientations [(111), (110), and (100)] of copper in copper–graphene composites, a strong orientational dependence on electronic conductivity is shown. Graphene exhibits near-ideal registries for (111) and (110) orientations, forming a connected network between grains that enables efficient carrier transport. The influence of non-carbon elements: nitrogen (N), oxygen (O), and sulfur (S) in graphene, representing possible structures in coal-based graphene are investigated. N, O, and S in graphene negatively impact the composite’s electronic conductivity relative to pristine graphene. A new method is introduced for visualizing the spatial distribution of electrical conduction activity in materials using the square of the electronic charge density near the Fermi level, based on the work of Mott. We call this technique the N2 method.

Computational analysis of 1T-MoS2: Probing the interplay of layer-dependent electronic structure, quantum capacitance, charge density and mechanical properties

To meet the high energy demand of society, a conversion to renewable energy sources has become essential and energy should be appropriately stored for future use. This has led to the development of energy-storing devices such as supercapacitors (SCs). To enhance capacitive behavior, the concept of quantum capacitance (CQ) is unveiled, which results from the confinement of electrons in their energy states. In this work, 1T phase of MoS2 is studied as it has received a lot of attention because of its wide applications in the energy storage devices and electronics. Here, the electronic structure, CQ and surface charge density (σ) of one, two and three-layered structures of 1T phase is studied using Density Functional Theory. No bandgap is obtained in the Density of States (DOS) and the bands plot of 1T structure indicates their metallic character and the DOS is continuous in all three layers. The CQ of three-layered structure dominates over the other two layers throughout the potential window. The larger CQ and σ values are obtained as 1718.06 μF cm−2 and -1299.50 μC cm−2 for three-layered structure at −0.27 V and −1 V respectively. For analyzing the mechanical strength, Young's modulus is evaluated for optimized structure by applying uni-axial strain. The value is obtained as 177.37 GPa, which is a measure of elastic deformation behavior. The results suggest that the capacitive performance of 1T MoS2 for SC applications is better and it can function as flexible cathode material for asymmetric SC applications.

Theoretical Studies of the Electronic and Thermoelectric Properties of PrIn3 and NdIn3 in Cubic Phase

The electronic and thermoelectric properties of AB3 (A =Pr, Nd and B=In) materials (crystallizing in the cubic structure) having space group Pm-3m (221) are studied using B3PW91 hybrid functional through the Full-Potential Linear Augmented Plane Wave (FP-LAPW) approach within the framework of Density Functional Theory (DFT). The calculated lattice parameters for PrIn3 and NdIn3 are 4.5668 Å and 4.5539 Å respectively. Electron-electron correlation effect is due to the 4f orbitals present in these materials and therefore, with the use of B3PW91 hybrid functional, band structure and density of states are calculated. When analyzing electron charge density, these materials showed a stronger ionic character. Band structure and density of state analysis confirms the metallic nature of the materials. Using the semi-empirical Boltzmann approach implemented in the BoltzTraP code, the thermoelectric parameters, such as Seebeck coefficient, figure of merit, electrical conductivity per relaxation time, and electronic thermal conductivity per relaxation time as a function of chemical potential, were computed at 500 K temperature gradient. PrIn3 showed highest Seebeck coefficient value, 50.68 μV/K among these compounds. The peak value of electrical conductivity per relaxation time and electronic thermal conductivity per relaxation time among these compounds is calculated for NdIn3 is 2.43 x 1020 1/Ωms and 22.50×1014 W/mKs.

Manganese doped tailored cobalt sulfide as an accelerated catalyst for oxygen evolution reaction

Developing an efficient, robust, and noble metal-free electrocatalyst that can catalyse oxygen evolution reactions (OER) remains a significant challenge. CoS2, a representative of pyrite form transition metal dichalcogenides, has recently been identified as an economical catalyst. Here, an incredibly quick and scalable technique for novel catalysts synthesized with the use of the microwave method was introduced. Manganese-doped cobalt sulphide (Mn-CoS2) showed outstanding OER with a very low overpotential of 227 mV at 10 mA cm−2. Exposure of surface atoms resulted in high electrochemical activity, where the defects facilitated charge and mass transfer along the nanostructure, allowing surface dependent electrochemical reactions to be performed more efficiently. The electronic properties of pristine and transition-metal-doped CoS2 structures were also investigated using density functional theory (DFT). To better understand transition metal’s dependent impact on crystal structure, orbital electronic participation, charge density, and charge transformation in both pristine and Mn-dopedCoS2 frameworks were calculated and analysized. Our synthesis approach is primarily commercial and extensible, overcoming synthesis challenge of transition metal sulphide nanostructures with prime quality and implying a potential for commercial uses.

Exploring the Optoelectronic and Photovoltaic Characteristics of Lead‐Free Cs2TiBr6 Double Perovskite Solar Cells: A DFT and SCAPS‐1D Investigations

AbstractIn recent times, the remarkable advancements achieved in the field of perovskite solar cells (PSCs) have sparked significant research efforts aimed at enhancing their overall performance because of their exceptional optoelectronic properties. Due to the toxicity of lead (Pb), the emergence of Ti‐based (Cs2TiBr6) double‐halide PSCs is regarded as a good alternative to Pb‐based PSCs. Here, density functional theory (DFT) calculations are performed to examine the prospect of Cs2TiBr6 perovskite as a layer of absorber for photovoltaic cells (SCs). These computations looked at the material's structural, optical, and electrical characteristics. The density of states (DOS) results demonstrate strong conductivity, principally provided by the 4p states of Br, whilst Ti‐3d and Cs‐5p orbital electrons offer insignificant contributions. The electronic band structure discloses a direct band gap of 1.534 eV. The covalent connections that exist between Ti and Br atoms and the robust electronic charge density around the Ti atom both demonstrate a significant buildup of electronic charge along the 100 planes. The dielectric function and the coefficient of absorption have significance irrespective of lower energies because it is extremely valuable for solar energy applications. The UV absorption peaks of Cs2TiBr6 have a maximum of ≈15.51 eV and are magnified with photon energy up to 2.46 eV, indicating that it may have potential for solar applications. This work also investigated a good combination of the hole transport layer (HTL) and electron transport layer (ETL) with the Cs2TiBr6 absorber layer. AZnO, Nb2O5, LBSO, and Zn2SnO4 are executed as the ETLs, and MoO3, CuAlO2, MEH‐PPV, ZnTe, CNTS, GaAs, MoS2, PTAA, Cu2Te, Zn3P2 are considered as the HTLs to identify the best HTL/Cs2TiBr6/ETL combinations using the SCAPS‐1D numerical simulation. Among all configurations, ITO/LBSO/Cs2TiBr6/CNTS/Au is examined as the best‐optimized structure of Ti‐based PSC, with JSC of 26.63 mA cm−2, a VOC of 1.123 V, FF of 82.94%, and a power conversion efficiency of 24.82%. To validate the findings, PV parameters like the effect of generation rate, recombination rate, J−V, and Q‐E characteristics are evaluated. The effect of series and shunt resistance and structure working temperature are explored to observe the effect of these on PSC devices. The accomplished outcomes suggest that Cs2TiBr6 can be viewed as an optimistic material for PSCs for its higher stability and environment‐friendly characteristics.

First-principle study of the ground-state crystal structure and optoelectronic response of CsPbX3 (X= Cl, Br, I) for photovoltaic applications

The optoelectronic response and ground state crystal structure of tetragonal (P4/mbm), orthorhombic (Pmnb) and monoclinic (P21/m) phases of CsPbX3 (X = Cl, Br, I) are studied for optoelectronic applications using first principle simulations. Electric field gradient (EFG) and magnetic hyperfine interactions are investigated to explore the charge distributions surrounding the nucleus and local magnetic environment of the atomic nucleus. The orthorhombic phase of these compounds is more stable having lowest ground-state energy compared to tetragonal and monoclinic phases. The understudied halide perovskites have direct band gap nature and spin orbit coupling (SOC) effect splits Pb-p and X-p orbitals at the edges of conduction and valence band (CB and VB) respectively. At the edge of VB, the strongly hybridized X-p and Pb-p orbital and direct band gap nature of CsPbX3 is excellent for the light absorption and photovoltaic (PV) applications. The n-i-p configuration (FTO/ETL/CsPbX3/HTL/Au) of the simulated structure shows that CsPbI3 has improved power conversion efficiency (PCE) of 22.48 % and 22.32 % and quantum efficiency (QE) about ∼80 % in tetragonal and monoclinic phases respectively. The Pb and Cs values of EFG tensor in z-direction (Vzz) are close to each other, which show that the distribution of electronic charge density is similar near these nuclei. Moreover, Cs-s orbital has negligible contribution and Pb-p and I-p orbitals have higher contribution in the hyperfine field (HFF). The negative HFF indicates the opposite HFF contribution.

Exploring Structural, Electronic, Vibrational, and Thermophysical Properties of Fe–Pt, Fe3–Pt, and Fe–Pt3 Alloys: A Density Functional Theory Study

Utilizing density functional theory, the structural, electronic, vibrational, and thermophysical properties of L10 FePt, L12 Fe3Pt, and L12 FePt3 alloys are meticulously analyzed. Employing projected augmented wave pseudopotentials alongside the Perdew–Burke–Ernzerhof exchange‐correlation function, equilibrium lattice constants are computed, aligning closely with existing data, thus validating our approach. To ascertain the dynamical stability of these alloys, phonon frequencies and density of states across high symmetry directions of the Brillouin zone are computed, affirming their stability with positive phonon frequencies throughout. Furthermore, the electronic band structure, the total and projected density of states, electronic charge density, and Fermi surfaces of the alloys are delved. The thorough analysis of phonon dispersion curves, electronic band structures, and the density of states, charge densities, and Fermi surfaces provides conclusive insights into the properties and behavior of the alloys. In essence, comprehensive investigation offers valuable insights into the thermophysical properties of L10 FePt, L12 Fe3Pt, and L12 FePt3 alloys, spanning equilibrium lattice constants, phonon characteristics, and electronic properties. These findings significantly augment the understanding of the structural stability, phonon dynamics, and electronic behavior exhibited by these alloys.

Unveiling the Structure of Metal–Nanodiamonds Bonds: Experiment and Theory

In this study, we conducted a theoretical simulation to compare the effects of various factors on the atomic and electronic structures and the magnetic properties of copper and gadolinium ions bonded to carboxylated species of (111) diamond surfaces. It was experimentally found that in the temperature range above 120 K, the magnetic moments of chelated Gd3+ and Cu2+ equal 6.73 and 0.981 Bohr magnetons, respectively. In the temperature range from 12 to 2 K, these magnetic moments sharply decrease to 6.38 and 0.88 Bohr magnetons. Specifically, we examined the effects of the number of covalent adatom–diamond substrate bridges, coordination of water molecules, and shallow carbon-inherited spins in the substrate on the physical properties of the metal center. Our simulation predicted that increasing the number of bonds between the chelated metal ion and substrate while decreasing the number of coordinating water molecules corresponded to a decrease in the magnetic moment of metal ions in a metal–diamond system. This is due to the redistribution of the electron charge density in an asymmetric metal–diamond system. By comparing our theoretical results with experimental data, we proposed configurations involving one and, in a minor number of cases, two surface –COO− groups and maximum coordination of water molecules as the most realistic options for Cu- and Gd-complexes.

Accelerating QM/MM simulations of electrochemical interfaces through machine learning of electronic charge densities.

A crucial aspect in the simulation of electrochemical interfaces consists in treating the distribution of electronic charge of electrode materials that are put in contact with an electrolyte solution. Recently, it has been shown how a machine-learning method that specifically targets the electronic charge density, also known as SALTED, can be used to predict the long-range response of metal electrodes in model electrochemical cells. In this work, we provide a full integration of SALTED with MetalWalls, a program for performing classical simulations of electrochemical systems. We do so by deriving a spherical harmonics extension of the Ewald summation method, which allows us to efficiently compute the electric field originated by the predicted electrode charge distribution. We show how to use this method to drive the molecular dynamics of an aqueous electrolyte solution under the quantum electric field of a gold electrode, which is matched to the accuracy of density-functional theory. Notably, we find that the resulting atomic forces present a small error of the order of 1 meV/Å, demonstrating the great effectiveness of adopting an electron-density path in predicting the electrostatics of the system. Upon running the data-driven dynamics over about 3ns, we observe qualitative differences in the interfacial distribution of the electrolyte with respect to the results of a classical simulation. By greatly accelerating quantum-mechanics/molecular-mechanics approaches applied to electrochemical systems, our method opens the door to nanosecond timescales in the accurate atomistic description of the electrical double layer.

DFT insight on stability, optoelectronic, and thermoelectric features of Na3XO (X = Cu, Ag) anti‐perovskites: Promising materials for sustainable energy applications

AbstractThe structural stability, elastic, optoelectronic, and thermoelectric characteristics of anti‐perovskites Na3XO (X = Cu, Ag) have been studied using density functional theory (DFT). The computed formation energy suggests these materials' potential synthesis and thermal stability. The structural and elastic properties of Na3CuO and Na3AgO anti‐perovskite compounds were analyzed using the Perdew–Burke–Ernzerhof (GGA‐PBE) generalized gradient potential approximation. The electronic and thermoelectric properties are calculated using the TB‐mBJ approximation. The materials are identified as direct narrow band gap semiconductors with band gaps of 0.65 and 0.43 eV. The analysis of two‐dimensional charge density contours indicates that Na3CuO and Na3AgO have a mixed bonding character, as validated by the investigation of electron charge density. We analyzed the optical properties of Na3CuO and Na3AgO, including dielectric function, refractive index, absorbance, optical reflectivity, and energy loss, using photon energy up to 6 eV. The investigated thermoelectric characteristics demonstrate figure of merit (ZT) values of 0.58 and 0.56 at room temperature. Consequently, the analyzed anti‐perovskites might address waste heat management requirements and sustainable energy solutions.

Atomically substitution engineering of europium-based dichalcogenides for enhancing tailored properties and superior applications

Transition-metal chalcogenides can be used as photoconductors and in optoelectronic devices. Research on the electronic properties of KBaSbSe3 has established that the parental compound possesses an indirect band gap of 2.0 eV. By europium doping, the material’s band structure experienced a transformation, resulting in a direct semiconducting behavior. This change was observed in spin-up and spin-down polarizations, with a bandgap of 1.5 eV. An analysis of the electron charge density (ECD) contour of the (101) crystallographic plane has been conducted to examine the bonding characteristics. Based on the reflectivity spectra, it is evident that both compounds exhibit a significant level of reflectivity, making them potentially suitable for shielding against visible and UV radiation. The calculations of birefringence demonstrate the ability to achieve phase matching for both observed compounds. Calculations were performed using Boltzmann transport theory to determine the Seebeck coefficient, Hall coefficient, electrical and thermal conductivities, and figure of merit. The compound KBaSbSe3 exhibits N-type at low temperatures and P-type due to a change in the Seebeck coefficient. Both compounds have excellent optical and thermal responses, making them promising materials for optoelectronic and thermoelectric devices.

Effect of Ni-doping on the structural and electronic properties of metal halide perovskite CsSnBr3: a DFT study

The structural and electronic properties of pure and Ni-doped perovskite CsSnBr3 in unit cell and supercell were computed using density functional theory at ambient pressure. Computed formation energy values of undoped and Ni-doped CsSnBr3 compounds show that these structures are stable. We used both standard DFT and HSE06 calculation in electronic band structure of pure and Ni-doped CsSnBr3 compounds. Since the band gap of undoped and Ni-doped CsSnBr3 compounds is located at the R symmetry point in the Brilloun zone, these compounds are materials with a direct band gap. In the HSE06 calculation, it was found that the band gap of 12.5% Ni doped-CsSnBr3 increased significantly from 1.1162 eV to 1.4343 eV. The electron charge density, Bader charge analysis and density of states reveal a strong covalent bond between Sn-Br (Ni-Br) and a strong ionic bond between Cs-Br. The direct electronic band gaps of undoped and Ni-doped CsSnBr3 perovskites in the visible energy range show that these compounds can be used effectively in optical applications.

First principles calculation of interface interactions and photoelectric properties of ZnSe/SnSe heterostructure.

Heterostructure engineering is an effective technology to improve photo-electronic properties of two dimensional layered semiconductors. In this paper, based on first principles method, we studied the structure, stability, energy band, and optical properties of ZnSe/SnSe heterostructure change with film layer. Results show that all heterostructures are the type-II band arrangement, and the interlayer interaction is characterized by van der Waals. The electron concentration and charge density difference implies the electron (holes) transition from SnSe to monolayer ZnSe. By increasing the layer of SnSe films, the quantum effects are weakened leading to the band gap reduced, and eventually show metal properties. The optical properties also have obvious change, the excellent absorption ability of ZnSe/SnSe heterostructures mainly near the infrared spectroscopy. These works suggest that ZnSe/SnSe heterostructure has significant potential for future optoelectronic applications.

Double Superconducting Dome of Quasi Two-Dimensional TaS2 in Non-Centrosymmetric van der Waals Heterostructure.

Two-dimensional van der Waals heterostructures (2D-vdWHs) based on transition metal dichalcogenides (TMDs) provide unparalleled control over electronic properties. However, the interlayer coupling is challenged by the interfacial misalignment and defects, which hinders a comprehensive understanding of the intertwined electronic orders, especially superconductivity and charge density wave (CDW). Here, by using pressure to regulate the interlayer coupling of non-centrosymmetric 6R-TaS2 vdWHs, we observe an unprecedented phase diagram in TMDs. This phase diagram encompasses successive suppression of the original CDW states from alternating H-layer and T-layer configurations, the emergence and disappearance of a new CDW-like state, and a double superconducting dome induced by different interlayer coupling effects. These results not only illuminate the crucial role of interlayer coupling in shaping the complex phase diagram of TMD systems but also pave a new avenue for the creation of a novel family of bulk heterostructures with customized 2D properties.