Shallow Band Research Articles

Design considerations of CdSe solar cells for indoor applications under white LED illumination

This work sheds light on the potential of Cadmium Selenide (CdSe) solar cells for indoor applications. CdSe boasts a wide direct bandgap, high carrier mobility, and a high absorption coefficient, making it an attractive candidate for harnessing ambient indoor light. Our study centers around an experimental solar cell architecture composed of FTO/CdSe/PEDOT:PSS/CuI/ITO, which exhibits a power conversion efficiency (PCE) of 6.00 %. Through a meticulous analysis of the core technological aspects of this cell, we successfully replicate the measured current-voltage characteristics and other experimental data, affirming the validity of our simulation modeling approach. Moving forward, we delve into the design and optimization of CdSe-based solar cells under white LED illumination. We emphasize the pivotal role of a double-hole transport layer (HTL) configuration over a single HTL, with a focus on optimizing the alignment between the HTL/back contact and HTL/absorber interfaces. The strategic incorporation of a heavily doped p-type HTL material, boasting both a deep valence band maximum (VBM) and a shallow conduction band minimum (CBM), is identified as paramount, especially for a deep VBM absorber like CdSe. Adding double HTL materials also facilitates efficient hole collection within the CdSe thin film while mitigating undesirable electron-hole recombination at the critical interface between the hole collection layer and the electrode. The implementation of a double HTL configuration based on CuI/ZnTe:Cu or CuI/BCS significantly enhances performance, resulting in a PCE in the order of 20 % under 200 lux and 2900 K LED illumination. Moreover, we introduce the single HTL design to provide other alternatives for efficiency boosting. Upon increasing the work function of the front contact, it is found that the valence band offset between the HTL and the absorber can be engineered, resulting in a PCE above 21.5 %.

Effect of intermolecular interactions and pharmacokinetic profile of antidiabetic agent (E)-N,N‑diethyl-2-(5(3‑hydroxy-4-methoxybenzylidene)-2,4-dioxothiazolidin-3-yl) acetamide

Diabetes is a prevalent disease in South India, posing a severe threat to public health. To tackle this issue, researchers are focusing on developing multi-targeted ligands, and one promising candidate is (E)-N,N‑diethyl-2-(5(3‑hydroxy-4-methoxybenzylidene)-2,4-dioxothiazolidin-3-yl)acetamide (DMDA). Geometry optimization of DMDA was carried out using density functional theory with 6–311+G(d, p) basis set to develop a theoretical model close to the previously synthesized and reported DMDA. Natural Bond Orbital analysis was conducted to scrutinize the phenomena of charge delocalization and electronic exchange interactions governing both intermolecular and intramolecular associations. Moreover, the vibrational characteristics of the molecule were elucidated through FT-IR and FT-Raman spectra. Lowest Unoccupied Molecular Orbital and Highest Occupied Molecular Orbital have also been explored to enhance understanding of the molecule's electronic structure and reactivity. Hirshfeld surface analysis was utilized to investigate the interactions between molecules within the crystalline lattice. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis elucidates the potential pharmacokinetic profile of DMDA. Molecular docking was performed to predict the binding site responsible for various interactions with the targeted protein. By combining these techniques, a comprehensive molecular description of DMDA has been generated.There are three prominent intramolecular interactions within the ambit of van der Waals radii, leading to stability of the molecule. The presence of a broad and shallow band with a significant red shift provides evidence for the strong intermolecular OH hydrogen bonding. DMDA complies with Lipinski's Rule of Five, highlighting its favorable characteristics for pharmaceutical efficacy. The negative binding energies determined by docking studies ascertain the potential sites of ligand-protein interaction leading to inhibition of α-amylase and α-glucosidase enzyme.

Sub-Band Assisted Z-Scheme for Effective Non-Sacrificial H2O2 Photosynthesis.

Photosynthesis of H2O2 from earth-abundant O2 and H2O molecules offers an eco-friendly route for solar-to-chemical conversion. The persistent challenge is to tune the photo-/thermo- dynamics of a photocatalyst toward efficient electron-hole separation while maintaining an effective driving force for charge transfer. Such a case is achieved here by way of a synergetic strategy of sub-band-assisted Z-Scheme for effective H2O2 photosynthesis via direct O2 reduction and H2O oxidation without a sacrificial agent. The optimized SnS2/g-C3N4 heterojunction shows a high reactivity of 623.0µmolg-1h-1 for H2O2 production under visible-light irradiation (λ>400nm) in pure water, ≈6 times higher than pristine g-C3N4 (100.5µmolg-1h-1). Photodynamic characterizations and theoretical calculations reveal that the enhanced photoactivity is due to a markedly promoted lifetime of trapped active electrons (204.9ps in the sub-band and >2.0ns in a shallow band) and highly improved O2 activation, as a result of the formation of a suitable sub-band and catalytic sites along with a low Gibbs-free energy for charge transfer. Moreover, the Z-Scheme heterojunction creates and sustains a large driving force for O2 and H2O conversion to high value-added H2O2.

Evaporated Nickel Oxide Films with Slow Annealing and Interface Modification for Perovskite Solar Cells.

Electron-beam-evaporated nickel oxide (NiOx) films are known for their high quality, precise control, and suitability for complex structures in perovskite (PVK) solar cells (PSCs). However, untreated NiOx films have inherent challenges, such as surface defects, relatively low intrinsic conductivity, and shallow valence band maximum, which seriously restrict the efficiency and stability of the devices. To address these challenges, we employ a dual coordination optimization strategy. The strategy includes low heating rate annealing of NiOx films and using an aminoguanidine nitrate spin coating process on the surfaces of NiOx films to strategically modify NiOx films itself and the interface of NiOx/PVK. Under the synergistic effect of this dual optimization method, the quality of the films is significantly improved and its p-type characteristics are enhanced. At the same time, the interface defects and energy level alignment of the films are effectively improved, and the charge extraction ability at the interface is improved. The combined treatment significantly improved the efficiency of inverted PSCs, from 17.85% to 20.31%, and enhanced device stability under various conditions. This innovative dual-coordinated optimization strategy provides a clear and effective framework for improving the performance of NiOx films and inverted PSCs.

Physical mechanism of secondary-electron emission in Si wafers

CMOS-compatible RF/microwave devices, such as filters and amplifiers, have been widely used in wireless communication systems. However, secondary-electron emission phenomena often occur in RF/microwave devices based on silicon (Si) wafers, especially in the high-frequency range. In this paper, we have studied the major factors that influence the secondary-electron yield (SEY) in commercial Si wafers with different doping concentrations. We show that the SEY is suppressed as the doping concentration increases, corresponding to a relatively short effective escape depth λ. Meanwhile, the reduced narrow band gap is beneficial in suppressing the SEY, in which the absence of a shallow energy band below the conduction band will easily capture electrons, as revealed by first-principles calculations. Thus, the new physical mechanism combined with the effective escape depth and band gap can provide useful guidance for the design of integrated RF/microwave devices based on Si wafers.

High‐Performance Blue Perovskite Films and Micro‐Arrays for Light‐Emitting Diodes with Ionic Liquid Interlayer

AbstractMetal halide perovskites have attracted considerable attention for light‐emitting diode (LED) applications due to their desirable optoelectronic properties including high brightness and color purity. However, the performance of blue perovskite LEDs (PeLEDs) remains inferior to their red and green counterparts. Herein, an ionic liquid (IL), specifically 1‐butyl‐3‐methylimidazolium tetrafluoroborate is introduced as the interlayer on the hole transport layer (HTL). This IL demonstrates a strong interaction with the perovskite emissive layer, resulting in effective defect passivation and a shallower valence band maximum. Consequently, nonradiative recombination is reduced, and hole injection is enhanced. Additionally, a soft lithography method employing a transfer process is successfully developed that enables precise micropatterning of the perovskite light‐emitting layer. Through these advancements, the IL‐modified PeLED exhibits pure blue emission at 470 nm with a maximum luminance of 891 cd m−2 and an impressive maximum EQE of 8.3%. Furthermore, the micro PeLED with an IL interlayer achieves a maximum luminance of 400 cd m−2 and a maximum EQE of 3.9%.

Enhanced Charge Balance for Efficient Electroluminescence from Cesium Copper Halides.

Cesium copper halides have the advantages of high photoluminescence quantum efficiency and good stability, making them attractive for replacing toxic lead halides in the field of perovskite light-emitting diodes (LEDs). However, due to their shallow conduction band and the lack of electron transport layers compatible with it, it remains a great challenge to achieve charge balance in LED devices. This drawback manifests as the accumulation of holes at the interface between the emitting layer and electron transport layer, resulting in nonradiative recombination. Here, we demonstrate an effective approach to address this issue by suppressing hole injection, which is realized through modification of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layer with polyethylenimine. This leads to cesium-copper-halide LEDs with a high external quantum efficiency of 5.6%, representing an advance in device architecture for efficient electroluminescence from cesium copper halides.

Inverted Solution-Processed Quantum Dot Light-Emitting Devices with Wide Band Gap Quantum Dot Interlayers.

Despite its benefits for facilitating device fabrication, utilization of a polymeric hole transport layer (HTL) in inverted quantum dots (QDs) light-emitting devices (IQLEDs) often leads to poor device performance. In this work, we find that the poor performance arises primarily from electron leakage, inefficient charge injection, and significant exciton quenching at the HTL interface in the inverted architecture and not due to solvent damage effects as is widely believed. We also find that using a layer of wider band gap QDs as an interlayer (IL) in between the HTL and the main QDs' emission material layer (EML) can facilitate hole injection, suppress electron leakage, and reduce exciton quenching, effectively mitigating the poor interface effects and resulting in high electroluminescence performance. Using an IL in IQLEDs with a solution-processed poly(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine) (TFB), HTL improves the efficiency by 2.85× (from 3 to 8.56%) and prolongs the lifetime by 9.4× (from 1266 to 11,950 h at 100 cd/m2), which, to the best of our knowledge, is the longest lifetime for an R-IQLED with a solution-coated HTL. Measurements on single-carrier devices reveal that while electron injection becomes easier as the band gap of the QDs decreases, hole injection surprisingly becomes more difficult, indicating that EMLs of QLEDs are more electron-rich in the case of red devices and more hole-rich in the case of blue devices. Ultraviolet photoelectron spectroscopy measurements verify that blue QDs have a shallower valence band energy than their red counterparts, corroborating these conclusions. The findings in this work, therefore, provide not only a simple approach for achieving high performance in IQLEDs with solution-coated HTLs but also novel insights into charge injection and its dependence on QDs' band gap as well as into different HTL interface properties of the inverted versus upright architecture.

PEIE-complexed SnO2 enabled low-temperature solution fabrication of high-performance CsPbI3 all-inorganic perovskite solar cells

CsPbI3 all-inorganic perovskite has attracted much attention due to its improved thermal stability compared with organic-inorganic hybrid counterparts. The shallow conduction band of CsPbI3 leads to an energy band mismatch between it and the widely used electron transport material SnO2, causing a severe loss in the performance. As a result, most high-efficiency inorganic perovskite solar cells are based on high-temperature sintered TiO2 with better energy band alignment. To exploit the potential of SnO2 in inorganic perovskite solar cells, SnO2 nanocrystals were complexed with ethoxylated polyethyleneimine (PEIE). This strategy affords continuous adjustment of SnO2 band structure by varying PEIE content, leading to an ideal energy band alignment with CsPbI3. The introduction of PEIE also promotes the growth of CsPbI3 films, resulting in larger grains. Moreover, improved charge extraction is achieved after PEIE introduction. As a result, the power conversion efficiency of CsPbI3 all-inorganic perovskite solar cells significantly increases from 11.61 % to 13.89 %. Our work provides a simple strategy to produce high-performance CsPbI3 all-inorganic perovskite solar cells with low-temperature solution process.

Three-dimensional potential energy surface for fission of 236U within covariant density functional theory* *Supported by the National Natural Science Foundation of China (11875225, 11790325, 11790320), the Special Fund from the China Nuclear Data Center, the Fundamental Research Funds for the Central Universities, and the Fok Ying-Tong Education Foundation

We calculate the three-dimensional potential energy surface (PES) for the fission of the compound nucleus U using covariant density functional theory with constraints on the axial quadrupole and octupole deformations as well as the nucleon number in the neck . By considering the additional degree of freedom , the coexistence of the elongated and compact fission modes is predicted for . Remarkably, the PES becomes shallow across a large range of quadrupole and octupole deformations for small , and consequently, the scission line in the plane extends to a shallow band, leading to fluctuations of several to ten MeV in the estimated total kinetic energies and of several to approximately ten nucleons in the fragment masses.

Spectroscopic Characterization of Impactites and a Machine Learning Approach to Determine the Oxidation State of Iron in Glass‐Bearing Materials

AbstractWe investigated a suite of impact glass‐bearing rocks using a multi‐analytical approach including visible‐near‐infrared diffuse reflectance spectroscopy, Mössbauer spectroscopy, and powder X‐ray diffraction. In order to better understand and interpret the obtained results, we built a database containing physical, chemical, and spectroscopic information on glasses and glass‐bearing materials using new results from this study and published works. We used the database to explore systematic relationships between parameters of interest and finally we applied several machine learning algorithms (support vector machine, random forests, and gradient boosting) to test the possibility to regress the oxidation state of iron from chemical and spectroscopic information. Our results show that even small amounts of mafic crystalline phases have a big influence on the spectral features of glass‐bearing rocks. Samples without mafic crystalline inclusions show the typical spectrum of glasses (two broad and shallow bands roughly centered around 1,100 and 1,900 nm) with minor variations due to bulk chemistry. We described a non‐linear relationship between average reflectance (average reflectance value between 500 and 1,000 nm), FeO + TiO2 content, grain size, and Fe3+/FeTOT. We tested the relation for the finer grain size (0–25 μm), and we qualitatively assessed how it is affected by grain size, Fe3+/FeTOT, and crystal content. Finally, we developed a machine learning pipeline to regress the Fe3+/FeTOT of glass‐bearing materials using the proposed database. Our machine learning calculations give satisfactory results (MAE: 0.0321) and additional data will enable the application of our computational strategy to remotely acquired data to extract chemical and mineralogical information of planetary surfaces.

Pinch-points to half-moons and up in the stars: The kagome skymap

Pinch point singularities, associated with flat band magnetic excitations, are tell-tale signatures of Coulomb spin liquids. While their properties in the presence of quantum fluctuations have been widely studied, the fate of the complementary non-analytic features -- shaped as half-moons and stars -- arising from adjacent shallow dispersive bands has remained unexplored. Here, we address this question for the spin $S=1/2$ Heisenberg antiferromagnet on the kagome lattice with second and third neighbor couplings, which allows one to tune the classical ground state from flat bands to being governed by shallow dispersive bands for intermediate coupling strengths. Employing the complementary strengths of variational Monte Carlo, pseudo-fermion functional renormalization group, and density-matrix renormalization group, we establish the quantum phase diagram. The U(1) Dirac spin liquid ground state of the nearest-neighbor antiferromagnet remains remarkably robust till intermediate coupling strengths when it transitions into a pinwheel valence bond crystal displaying signatures of half-moons in its structure factor. Our work thus identifies a microscopic setting that realizes one of the proximate orders of the Dirac spin liquid identified in a recent work [Song, Wang, Vishwanath, He, Nat. Commun. 10, 4254 (2019)]. For larger couplings, we obtain a collinear magnetically ordered ground state characterized by star-like patterns.

Chemical Trends of Surface Reconstruction and Band Positions of Nonmetallic Perovskite Oxides from First Principles

An evolutionary algorithm search in combination with first-principles calculations is performed to systematically predict the reconstructed surface structures of nonmetallic perovskite oxides. Four types of lowest-energy reconstruction patterns are obtained for the macroscopically stoichiometric (001) surfaces of NaTaO3, KTaO3, CaTiO3, SrTiO3, YAlO3, and LaAlO3 as representatives of A+B5+O3, A2+B4+O3, and A3+B3+O3 systems. We explain chemical trends in the surface energies and band positions of 10 perovskite oxides, additionally including KNbO3, BaTiO3, BaZrO3, and LaGaO3, in terms of the atomic environments at the outermost reconstructed surface layers. Regaining A–O (B–O) coordination numbers and bond lengths at the surfaces is found to stabilize the A2+B4+O3 and A3+B3+O3 (A+B5+O3) surfaces. Decreasing the coordination number of cation A (B) leads to shallow (deep) valence band maxima and conduction band minima relative to the vacuum level. Our study provides general insights into the surface reconstruction and band alignment of nonmetallic perovskite oxides.

Extremely Shallow Valence Band in Lanthanum Trihydride.

Hydride ions (H-) in solvents are chemically active anions with strong electron-donating ability and are used as reducing agents in organic chemistry. Here, we evaluate the energy level of 1s-electrons in H- accommodated in solid lanthanum hydrides, LaHx (2 ≤ x ≤ 3), by photoemission (ultraviolet photoelectron and photoelectron yield spectroscopies) measurements and density functional theory calculations. We show that a very shallow valance band maximum with an ionization potential of 3.8 eV is attained in LaH3 and that the primary cause is attributed to the small electronegativity of hydrogen and the significant bonding-antibonding interaction between neighboring H-s with a close separation originating from the H-stuffed fluorite-related structure. These results encourage the challenge for p-type conduction in hydride semiconductors and provide a clue to the chemical understanding of polyhydride superconductors.

Breakdown of Adiabatic Superconductivity in Ca-Doped h-BN Monolayer

In the present paper, we report the breakdown of the adiabatic picture of superconductivity in a calcium-doped hexagonal boron nitride (Ca-h-BN) monolayer and discuss its implications for the selected properties of this phase. In particular, it is shown that the shallow conduction band of the Ca-h-BN superconductor potentially cause a violation of the adiabatic Migdal’s theorem. As a result, the pivotal parameters that describe the superconducting state in Ca-h-BN are found to be notably influenced by the non-adiabatic effects. This finding is described here within the vertex-corrected Eliashberg formalism that predicts a strong reduction of the order parameter, superconducting transition temperature and superconducting gap in comparison to the estimates obtained in the framework of the adiabatic theory. The observed trends are in agreement with the recent results on superconductivity in hexagonal monolayers and confirm that the non-adiabatic effects have to be taken into account during the design of such future low-dimensional superconductors.

Role of hydrogen in the post-annealing treatments for amorphous In-Ga-Zn oxide thin films

In-Ga-Zn-O thin films were prepared by magnetron sputtering at different deposition temperatures and annealed in pure hydrogen (H2) and nitrogen (N2), respectively. The carrier concentration increased to 9.6 × 1019 cm−3 and the Hall mobility reached to 9.3 cm2V-1s−1 upon 300 ℃ annealing in N2. However, the Hall mobility decreased to 4.3 cm2V-1s−1 upon thermal annealing in H2 despite of the carrier concentration increased to 1.1 × 1020 cm−3. Spectroscopic ellipsometry results show that the increased carrier concentration is related to the incremental shallow band edge state (D1), and the increasing of deep band edge state (D2) will lead to a rise in trap density and a reduction in Hall mobility.

Pseudogap and strong pairing induced by incipient and shallow bands in quasi-two-dimensional KCa2Fe4As4F2

The optical properties of $\mathrm{K}{\mathrm{Ca}}_{2}{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}{\mathrm{F}}_{2}$ (K12442, ${T}_{c}=33.5$ K) and $\mathrm{K}{\mathrm{Ca}}_{2}{({\mathrm{Fe}}_{0.95}{\mathrm{Ni}}_{0.05})}_{4}{\mathrm{As}}_{4}{\mathrm{F}}_{2}$ (Ni-K12442, ${T}_{c}=29$ K) have been examined at a large number of temperatures. For both samples, a nodeless superconducting gap is clearly observed in the optical conductivity at 5 K. The superconducting gap $\mathrm{\ensuremath{\Delta}}\ensuremath{\simeq}8.7$ meV ($2\mathrm{\ensuremath{\Delta}}/{k}_{\text{B}}{T}_{c}\ensuremath{\simeq}6.03$) in K12442, pointing towards strong-coupling Cooper pairs, but in sharp contrast, $\mathrm{\ensuremath{\Delta}}\ensuremath{\simeq}4.6$ meV ($2\mathrm{\ensuremath{\Delta}}/{k}_{\text{B}}{T}_{c}\ensuremath{\simeq}3.68$) in Ni-K12442, which agrees with the BCS weak-coupling pairing state. More intriguingly, below ${T}^{*}\ensuremath{\simeq}75$ K, the optical conductivity of K12442 reveals a pseudogap that smoothly evolves into the superconducting gap below ${T}_{c}$, while no such behavior is detected in the electron-doped Ni-K12442. The comparison between the two samples suggests that the pseudogap and strong-coupling Cooper pairs in K12442 may be intimately related to the shallow and incipient bands. We provide arguments supporting a preformed pairing mechanism of the pseudogap, but at the moment a magnetic scenario cannot yet be excluded.

(Invited) (Photo)Electrochemical Cells for Hydrogen Production and Carbon Dioxide Utilization

Photoelectrochemical (PEC) and electrochemical cells can produce hydrogen from water and/or can produce useful chemicals from carbon dioxide, and, thus, are the key technologies for construction of carbon neutral society.Direct water splitting using photoelectrochemical cell is one of the promising means to produce hydrogen utilizing solar energy. The most important issue for photoelectrode the central of photoelectrochemical cell is narrow bandgap combined with large reaction driving force. Cu(In,Ga)Se2 (CIGS) which is employed as an absorber material in photovoltaic devices is one of the promising photocathode materials because of its long absorption edge of >1000 nm. [1] However, its driving force for water splitting is limited because of relatively shallow valence band maximum (VBM). The solid solution between ZnSe and CIGS (ZnSe-CIGS) is one of the promising candidates of photocathode material for water splitting because of its long absorption edge, ~900 nm, and large driving force, ~1.0 V. [2] In the present study, we investigated introduction of tellurium during ZnSe-CIGS thin films, and found the tellurium introduction increase grain size of ZnSe-CIGS film. The sequential deposition of Ga-rich layer and In-rich layer resulted in formation of composition gradient which facilitate charge separation thorough conduction band minimum (CBM) gradient. The ZnSe-CIGS base photocathode prepared with employing tellurium introduction and composition gradient showed significantly increased incident photon-to-current conversion efficiencies (IPCEs), close to unity. [3]The electrochemical cell with gas diffusion electrode (GDE) for carbon dioxide reduction reaction (CO2RR) can produce useful chemicals efficiently. Copper species are the catalysts with capable of producing C2 products such as C2H5OH and C2H4. In the present study, Cu2O was examined as an electrocatalyst for CO2RR. A GDE composed of carbon paper coated with Cu2O by electroplating method showed C2H4 production with faradaic efficiency (FE) of >50% and C2H5OH production with FE of >20% under the optimized conditions for >10 hours.References H. Kumagai, T. Minegishi, N. Sato, T. Yamada, J. Kubota, K. Domen, J. Mater. Chem. A, 3, 8300 (2015). H. Kaneko, T. Minegishi, M. Nakabayashi, N. Shibata, K. Domen, Angew.Chem. Int. Ed. 55,15329 (2016). T. Minegishi, S. Yamaguchi, M. Sugiyama, Appl. Phys. Lett. 119, 123905 (2021).

Improved Photocatalytic Activities of g-C3N4 Nanosheets by B Doping and Ru-Oxo Cluster Modification for CO2 Conversion

g-C3N4 is a promising photocatalyst for CO2 conversion owing to its outstanding reduction potential. However, its shallow valence band position and sluggish water oxidation reaction restrict the overall CO2 photoreduction process. Herein, g-C3N4 nanosheets are first doped with B through thermal treatment of mixed NaBH4 and subsequently modified with highly dispersed Ru-oxo clusters by using tailored chitosan oligomers. The optimal Ru-oxo modified B-doped g-C3N4 exhibits an exceptional photocatalytic CO2 conversion rate with 22-fold improvement compared with pristine CN. Based on the results of electron paramagnetic resonance, atmosphere-controlled surface photovoltage spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy, etc., it is confirmed that the improved photoactivities are attributed to the downward shift of the valence band to obtain the strong driving force for water oxidation along with extension of the visible light response region by B doping and to the capture of photogenerated holes to enhance charge separation and then to accelerate the water oxidation process from the modified Ru-oxo clusters.

Study on formation, electronic states evolution and spin polarization transition for MnGa compound under an anisotropic stress

The Formations, stabilities, evolutions of geometries, electronic states together with the spin polarization transitions involved with magnetic properties of the MnGa compound under c axis anisotropic stress are systematically studied within the framework of density functional theory analyzing method. The results show that the anisotropically geometric expansion can be induced under stress. There are five kinds of atomic distances within the compound, with larger distance values for Mn–Mn and Ga–Ga, and smaller distances for Mn–Ga. The induced atomic distance fluctuations are also anisotropic, corresponding to the anisotropic binding strength regulations. The compound under stress is more stable. The s orbital releases electrons, the p and the d orbitals accept electrons for Mn. The s orbital and the d orbital release electrons, the p orbital traps electrons for Ga. The Mn1 and Mn2, Ga1 and Ga2 have diversified configurations under stress. A transition of ionic state of Mn2 is observed. Electrons transfers occur between orbitals and species under stress. The MnGa has anisotropic conductor band structure. The effective mass of conduction band as well as shallow valence band are enhanced under stress. The electronic band experiences a transition from semimetal into metal. The s, p and d electrons form the conduction band and shallow valence band. The d electrons mainly form the deep valence band, too. The localization at −16.8eV of d electrons is weakened under stress. The Mnd electrons get less responsible for the spin state under stress. The Mn1 and Mn2 turn to exhibiting distinctively diverse profiles, the Ga1 and Ga2 turn to exhibiting the same profiles under stress. The Mn shows strong atomic magnetic moment than that of Ga.