Wide Energy Gap Research Articles

Facile route to prepare hybrid TiO2-SnO2 DSSCs

Using a hybrid sol–gel and electrospinning method, one-dimensional SnO2 nanostructures were fabricated with average diameters of 86 and 53 nm after calcination at 500 and 600 °C, respectively. The morphology and structure of the obtained materials were analyzed using transmission and scanning electron microscopy (TEM, SEM) and X-ray diffraction (XRD). Additionally, the chemical composition was confirmed using Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy. Based on BET and BJH analysis, the specific surface area and porosity of SnO2 nanowires were evaluated. The optical properties of the prepared materials were investigated by UV–Vis spectrophotometer. The analyses confirmed that polycrystalline SnO2 nanostructures composed of two polymorphic varieties tetragonal and rhombohedral were derived, whose calcination temperature had a significant effect on the diameter, specific surface area and energy gap width. The fabricated nanowires were added at 5 and 10 mg to P25 TiO2 paste and screen-printed onto FTO substrate. After drying and calcination, the TiO2 NPs-SnO2 NWs hybrid photoanode was charged with dye, electrolyte and platinum electrode were applied and its performance was investigated in a dye-sensitized solar cell (DSSC). The study showed that the addition of 5 mg SnO2 increased the cell efficiency by 12% compared to the standard P25. The results presented in this study are a good base for further research and shows how important it is to work on the application of nanomaterials produced by the electrospinning technique, which will help to develop and increase the efficiency and competitiveness of DSSC.

Vibrationally-resolved absorption and fluorescence spectra of chemically modified 2D hexagonal boron nitride quantum dots

The vibrationally-resolved absorption and fluorescence spectra of square hexagonal boron nitride (shBN) quantum dot are studied using time dependent DFT calculations. The details of the first excited state in the UV–Vis absorption spectrum significantly clarified by the inclusion of vibronic transitions. The lowest vibronic transition in the absorption or fluorescence spectra shows that shBN has a wide optical energy gap of 4.93 eV. The absorption-fluorescence spectra indicate that doping with three C-atoms (doping percentage of 6%) decreases the optical energy gap to 0.46 eV. Doping also significantly enhances the interaction with the incident photon due to the boosted dipole strength.

Surface functionalization of Si6Li6 cluster with superalkalis to achieve high nonlinear optical response: A DFT study

In this study, the nonlinear optical (NLO) response of pure and superalkali (Li3O, Na3O, and K3O) doped Si6Li6 clusters has been explored. The doping of superalkalis on the Si6Li6 cluster significantly narrowed the wide HOMO-LUMO energy gap (5.27 eV) of the pure Si6Li6 cluster up to 3.83 eV. All superalkali doped clusters reveal electride nature based on the HOMOs’ electron density. The thermodynamic stability of these electrides is anticipated through their interaction energies with the highest value (3.90 eV) for Si6Li6-Li3O. The NLO properties of superalkali doped Si6Li6 electrides are investigated through first and second-order hyperpolarizabilities. These complexes exhibit large first hyperpolarizabilities as compared to pristine Si6Li6. Among superalkali doped clusters, Si6Li6-K3O showed the highest first hyperpolarizability of 1.42 × 104 au. The small crucial excitation energies are responsible for such a high NLO response. For dynamic NLO response, electro-optic Pockel’s effect and second harmonic generation are calculated. A very large quadratic NLO response (3.61 ×10−9 au) is observed for the Si6Li6-Li3O complex. The quantum theory of atoms in molecules (QTAIM) analysis shows the electrostatic interaction between interacting species. All the electrides exhibit ultrahigh transparency in the UV–VISIBLE region. These intriguing results are self-serving to promote promising applications of Si6Li6-based clusters in high-performance nonlinear optical materials.

Superior ferromagnetic and electrical properties: High purity multiferroic Bi0.98M0.02FeO3 (M = La, Pr, Gd) compositions

Enhanced resistivity and full wide ranging-saturated ferromagnetic loop with high saturation magnetization were originated in light Gd-modified BiFeO3. In this study, high purity BiFeO3, Bi0.98La0.02FeO3, Bi0.98Pr0.02FeO3 and Bi0.98Gd0.02FeO3 compositions have been synthesized via facile glycine-autocombustion technique. Crystalline rhombohedral lattice corresponding to BiFeO3 single phase was formed in all samples. Reengineering of band gap structure and lattice dimensions alongside the XRD peaks shifts verified the replacement of La3+, Pr3+/4+ and Gd3+ ions for Bi3+-sites into BiFeO3. The SEM micrographs of Bi0.98La0.02FeO3 demonstrated the formation of network of porous structure with a root like-shape while particles with chip-wavy shape were seen for Bi0.98Pr0.02FeO3. The micrograph of Bi0.98Gd0.02FeO3 sample displays highly porous arrangements with a spongy shape. The BET surface area, pore volume and pore size of pure BiFeO3 were determined to be 3.1478 m2/g, 0.1260 cm3/g and 9.6 nm, respectively. The measurements display that the surface area and pore volume of BiFeO3 were increased due to Gd doping to reach to 7.3044 m2/g and 0.8561 cm3/g, respectively. Optically, La, Pr and Gd doping engineered the energy gap width of BiFeO3 (2.09 eV), resulting in band gap of 2.16, 2.14, and 2.1 eV, respectively. Based on band gap, high refractive index (n) values greater than 2.5 were detected for all samples which are applicable values for many optical applications. La, Pr and Gd ions have a positive effect on reducing the energy dissipation-dielectric loss factor and also enhancing the resistivity of BiFeO3. The M−H loops indicated that the magnetic property of 2 wt% Gd-modified BiFeO3 was highly enhanced in comparison to that of BiFeO3. Bi0.98Gd0.02FeO3 composition displayed superior values of saturation magnetization of 2.064 emu/g, remanent magnetization (Mr) of 0.246 emu/g and coercivity (Hc) of 125.8 Oe.

Effects of lanthanide ions on the structure and electrical properties of Aurivillius Bi3TiNbO9 high temperature piezoelectric ceramics

Aurivillius Bi3TiNbO9 has a very high Curie temperature (Tc), but the piezoelectric coefficient (d33) is very low, and the influence of ions with different radii on its performance is not clear. High temperature piezoelectric ceramics Bi2.99(Li0.5Ln0.5)0.01TiNbO9 (BTNO-1LiLn, Ln = La, Nd, Gd, and Er) were prepared by solid state reaction sintering, and its microstructure, piezoelectric properties and electrical conductivity were systematically studied. The Tc of BTNO-1LiLn increases with the decrease of Ln3+ ions radii. BTNO-1LiEr obtains the highest d33 of 10.6 pC/N. Considering the cation disorder of A-site and bismuth layer of calcium titanium layer in Aurivilius structure, the crystal structures of BTNO-1LiLa with special occupation and BTNO-1LiEr with the best performance are refined, and the source of spontaneous polarization (Ps) is analyzed. It is proved that different occupation will have different effects on the high temperature piezoelectric properties and fatigue cycle properties of BTNO based ceramics. Finally, the band structure of BTNO pure ceramic based on the first principle is calculated. By comparing the activation energy and band gap width, it is indicated that (Li0.5Ln0.5)2+ ions entering BTNO will form impurity energy levels and form p-type semiconductors. This study provides a theoretical basis for better performance of BTNO based high temperature piezoelectric ceramics.

New deep blue fluorophores based on benzo[d]thiazole group as acceptor core: Theoretical, synthesis, photophysical and electroluminescent investigation

Deep-blue organic emitters have attracted considerable attention from both industrial as well as academic research in organic light-emitting diodes (OLEDs). In this context, three novel deep blue fluorophores based on benzothiazole 2-(4'-(1,4,5-triphenyl-1H-imidazole-2-yl)-[1,1′-biphenyl]-4-yl)benzo [d]thiazole (PHBISN), 2-(4'-(1-(4-(tert-butyl)phenyl)-4,5-diphenyl-1H-imidazole-2-yl)-[1,1′-biphenyl]-4-yl)benzo [d]thiazole (PTBISN) and 2-(4'-(4,5-diphenyl-1-(3-(trifluoromethyl)phenyl)-1H-imidazole-2-yl)-[1,1′-biphenyl]-4-yl)benzo [d]thiazole (m-CFBISN) were designed and synthesized. The fluorophores were structurally characterized and a detailed computational study reveals the compounds with wide energy gap (>3eV). The thermal properties, photophysical and electronic properties were systematically investigated. Photoluminescence and electroluminescence study shows fluorophores with deep blue emission. Novel synthesized fluorophores exhibit good performance for deep-blue solution-processed OLEDs. The doped device based on PTBISN shows the highest performance with deep blue electroluminescent and maximum EQE 1.5% with CIE color coordinates of (0.15, 0.08), which is near to the blue standard (0.14, 0.08) of the National Television System Committee (NTSC).

Pulsed laser deposition grown non-stoichiometry transferred ZnGa2O4 films for deep-ultraviolet applications

It is generally known that Zn volatilization would result in a serious degradation in film quality and device performance during a non-stoichiometric ZnGa2O4 target ablation. This work highlights the effect of various substrate temperatures and partial oxygen pressures on the microstructural and optoelectronic properties of stoichiometric ZnGa2O4 films. First-principle studies have been performed to calculate the formation energy per atom of pure Ga2O3, ZnGa2O4, and ZnO to understand the mechanism of preparing ZnGa2O4 by pulsed laser deposition, revealing the stability of Ga2O3 > ZnGa2O4 > ZnO under various growth parameters. Sufficient oxygen partial pressure should be introduced to deposit a large amount of ZnO, and then the Ga:Zn ratio can be adjusted to the most suitable 2:1 by controlling the substrate temperature and post-annealing heat treatment. The X-ray diffraction analysis revealed the high crystalline nature of stoichiometric ZnGa2O4 film. The average transmittance of above 80% and wide energy gap of 5.18 eV revealed the potential of stoichiometric ZnGa2O4 film in deep-ultraviolet photodetectors. This stoichiometric ZnGa2O4 film exhibited the photo/dark current ratio of 3.63 × 104 and high responsivity of 1.97 A/W at the bias of 5 V under the illumination wavelength of 220 nm for deep-ultraviolet applications.

Novel and promising material (CuInSn3S8) for photovoltaic and optoelectronic applications

Novel thin films of CuInSn3S8 (CISS8) have been synthesized using the spray pyrolysis approach. This is the first time to prepare such interesting material which could be an up-and-coming candidate in the transparent conductive thin films family. Basic characterizations have been employed to inspect the nature and morphology of the deposited films. The film's surface is quite uniform and homogeneous. Also, they are polycrystalline with a monoclinic structure. Furthermore, the network topology of CuInSn3S8 material has been investigated to understand its compactness nature. This has been achieved through evaluating several interesting indices such as density, molar volume, free volume percentage, packing density, compactness, and lone-pair of electrons. In addition, linear/nonlinear optical and optoelectrical properties have been studied. Films have revealed a wide energy gap that varies between (3.86 and 3.79 eV) with the direct optical transition. Moreover, they have presented high infrared reflectance, adequate optical transmittance within the visible spectrum, and the tendency of being n-type semiconductors. Besides, films have exhibited high values of optical conductivity and nonlinear optical parameters. A satisfactory linkage has been made betwixt all of the determined indices either the structural, network topology, and optical/optoelectrical ones. The obtained findings refer to the rising of a new star on the horizon of photovoltaic and optoelectronic applications fields.

Extreme learning machine computational method of modeling energy gap of doped zinc selenide nano-material semiconductor

Zinc selenide (ZnSe) semiconductor belongs to a class of wide energy gap material with low visible region optical absorption, high optical coefficient (nonlinear) and fascinating optoelectronic as well as photocatalytic features which foster and strengthen its applications in resisting thermal shock, photoelectric fields (which include dielectric mirrors, shot wavelength lasers and light emitting diode), buffer layer of solar cell and many photocatalytic environmental cleanliness applications. Nanostructured ZnSe semiconductors occupy a special place in application domain due to the characteristic features attached to the crystallite size of the material which include high fluorescence quantum yields, solvent dispersibility and adjustable emission color among others. Effective utilization of nanostructured ZnSe semiconductor involves tuning of its energy gap through doping mechanisms which is accompanied with distortion in the parent lattice structure. In this contribution, extreme learning machine (ELM) computational intelligent method is proposed for predicting the band gap energy of doped ZnSe nanostructured semiconductor using the material crystallite size and lattice parameter as descriptors to the models. The developed ELM based model using sine (Sine), sigmoid (Sig) and transig (Trang) activation functions were compared with the existing SVR-GA and SPR models in the literature using various performance metrics. The developed Sine-ELM model shows superior performance over Sig-ELM, Trang-ELM, SVR-GA (2021) and SPR (2021) models with performance improvement of 12.74%, 64.89%, 68.87% and 75.62% using mean squared error (MSE) metric for testing data samples. The superiority of the model developed was further justified through validation with external set of data. The precision and superiority of the ELM based models developed would eventually ease quick characterization and tuning of energy gap of ZnSe nanostructured semiconductors for various applications.

Mid-Infrared HgCdTe Heterostructure and Its Potential Application to APD Operation

Mid-wave infrared HgCdTe photodiode grown by metal-organic chemical vapor deposition was characterized for its use in avalanche operation. N^&#x002B;/N/p/P/P^&#x002B;/n^&#x002B; heterostructure meets the assumptions of the separated absorption and multiplication design. The p-type absorber, with an assumed Cd molar composition of 0.305, was optimized to operate up to <inline-formula> <tex-math notation="LaTeX">$4.4 ~\mu \text{m}$ </tex-math></inline-formula> at 230 K. The multiplication region is contained within the N layer with a wider energy gap (<inline-formula> <tex-math notation="LaTeX">$\text{x}_{\textit {Cd}}=0.33$ </tex-math></inline-formula>). Satisfactory gain of &#x007E;50 was achieved for a moderate reverse bias of &#x2212;3.5 V and a temperature of 160 K.

Fast generation of cat states in Kerr nonlinear resonators via optimal adiabatic control

Macroscopic cat states have been widely studied to illustrate fundamental principles of quantum physics as well as their applications in quantum information processing. In this paper, we propose a quantum speed-up method for the creation of cat states in a Kerr nonlinear resonator (KNR) via optimal adiabatic control. By simultaneously adiabatic tuning the cavity-field detuning and driving field strength, the width of the minimum energy gap between the target trajectory and non-adiabatic trajectory can be widened, which allows us to accelerate the evolution along the adiabatic path. Compared with the previous proposal, preparing cat states only by controlling two-photon pumping strength, our method can prepare the target state with a shorter time, a high-fidelity and a large non-classical volume. It is worth noting that the cat state prepared here is also robust against single-photon loss. Moreover, when we consider the KNR with a large initial detuning, our proposal will create a large-size cat state successfully. This proposal for preparing cat states can be implemented in superconducting quantum circuits, which provides a quantum state resource for quantum information encoding and fault-tolerant quantum computing.

Highlights on the structural, optical, and optoelectrical properties of novel InSbO3 thin films synthesized by chemical bath deposition

A felicitous attempt has been attained to synthesize a novel ternary oxide InSbO3. The InSbO3 films have been grown via the chemical bath deposition (CBD) approach. X-ray diffraction (XRD) investigations presented the amorphous nature of as-deposited layers. The morphology, optical, and optoelectrical features have been scrutinized to recognize the film's essence. Films revealed the state of allowed indirect transition and the energy gaps were decreased from 4.08 eV to 3.46 eV via boosting the deposition time from 1 to 5 h. The good optical properties like the high transparency, wide energy gap, and n-type semiconducting behavior propose the possibility of employing our films in numerous optical implementations, especially in various display apparatus, and in thin-film solar cells as a promising window layer. Moreover, films exhibited high values of nonlinear optical parameters. Therefore, the InSbO3 films could also act as a promising material in nonlinear devices.

Strong four-phonon scattering in monolayer and hydrogenated bilayer BAs with horizontal mirror symmetry

Recently, the important role of high-order anharmonic phonon–phonon interactions has been revealed in several materials, such as cubic boron arsenide (BAs), in which the wide phononic energy gap is found to be a critical factor causing the importance of four-phonon scattering. In this work, by solving the Boltzmann transport equation, we show that the four-phonon scattering has a significant impact on the thermal transport in honeycomb structured monolayer BAs (m-BAs) and its hydrogenated bilayer counterparts (bi-BAs). The lattice thermal conductivity (κL) values of all these structures are reduced after considering four-phonon scattering. Particularly, a huge drop in κL as large as 80% is observed for m-BAs compared to the case without four-phonon scattering, which is mainly caused by the suppression of phonon lifetimes. More interestingly, as opposed to the case of graphene, κL of m-BAs is abnormally lower than its bi-BAs counterparts, which is attributed to the much larger phonon scattering rate in m-BAs compared to that in bi-BAs. By further comparing BAs sheets with and without horizontal mirror symmetry, it is found that the contribution of flexural acoustic phonon exhibits most significant reduction in both mi-BAs and bi-BAs with horizontal mirror symmetry after including four-phonon scattering. This work provides physical understanding of the role of mirror symmetry and high-order phonon scattering on the thermal transport in two-dimensional materials.

Carbon nanotubes with periodic vacancy defects to phenine nanotubes: A DFT study

In the present paper a systematic investigation has been performed to study the structural and electronic properties of phenine nanotubes (pNT(n,n)) within framework of density functional theory. pNT (n,n) molecules with n = 3–15 have been obtained by introducing periodic 6 atom vacancy defects periodically in pristine carbon nanotubes. Our results have shown that symmetric pNT(n,n) structures can only be formed with n = 3, 6, 9, 12 and 15. For other values of n, non-symmetric hybrid pNT(n,n) structures were obtained. The symmetric pNT(n,n) molecules have exhibited perfectly ordered structures, with a periodic vacancy and large voids up to 63% of the molecule. The bond filling index and atom filling index of all symmetric pNT(n,n) molecules was found to be 63%and 57% respectively. The binding energy calculation have shown that pNT(n,n) structures are quite stable, however they are slightly less stable in comparison to non-symmetric pNT(n,n). All pNT(n,n) molecules have been found to be semiconducting in nature with wide HOMO-LUMO energy gap with HOMO-LUMO gap of pNT(n,n) in the range of 1.58 eV–2.98 eV. The HOMO-LUMO gap varies in an oscillatory manner with increase in the size of pNT(n,n) molecules with maximum values for symmetric structures. The results are in agreement with the available experimental results. The pNT(n,n) molecules with large stability, huge voids and tunable electronic properties offers many interesting applications in optoelectronic devices.

Realization of a Half Metal with a Record-High Curie Temperature in Perovskite Oxides.

Half metals, in which one spin channel is conducting while the other is insulating with an energy gap, are theoretically considered to comprise 100% spin-polarized conducting electrons, and thus have promising applications in high-efficiency magnetic sensors, computer memory, magnetic recording, and so on. However, for practical applications, a high Curie temperature combined with a wide spin energy gap and large magnetization is required. Realizing such a high-performance combination is a key challenge. Herein, a novel A- and B-site ordered quadruple perovskite oxide LaCu3 Fe2 Re2 O12 with the charge format of Cu2+ /Fe3+ /Re4.5+ is reported. The strong Cu2+ (↑)Fe3+ (↑)Re4.5+ (↓) spin interactions lead to a ferrimagnetic Curie temperature as high as 710 K, which is the reported record in perovskite-type half metals thus far. The saturated magnetic moment determined at 300 K is 7.0 μB f.u.-1 and further increases to 8.0 μB f.u.-1 at 2 K. First-principles calculations reveal a half-metallic nature with a spin-down conducting band while a spin-up insulating band with a large energy gap up to 2.27eV. The currently unprecedented realization of record Curie temperature coupling with the wide energy gap and large moment in LaCu3 Fe2 Re2 O12 opens a way for potential applications in advanced spintronic devices at/above room temperature.

Construction of BODIPY functional ZIF-8 with improved visible light-induced antibacterial activity

Developing novel bactericide and therapeutic strategy to inhibit bacterial –resistance has become the attractive research area. Light-activated nano-antibacterial agents have become the current research hotspot due to their multimodal antibacterial effect. However, the poor response to visible light and wide energy gap greatly reduce nano-material photo-induced antibacterial activity. Herein, a novel visible light-induced nano-antibacterial composite (BODIPY-ZIF-8) are constructed by introducing boron dipyrromethene (BODIPY) into the framework of ZIF-8. BODIPY-ZIF-8 are found to be the microporous hollow spheres with specific surface area of 612.30 m2/g and exhibit extraordinary photo-induced antibacterial activity against E. coli and S. aureus in comparison to the reported ZIF-8 based antibacterial agents. The successful introduction of BODIPY decreases the band gap energy and increases the light absorption, simultaneously BODIPY acts as a structure-directing agent of controlling the morphology of BODIPY-ZIF-8. The study of antibacterial mechanism indicates that BODIPY-ZIF-8 show synergistic antibacterial effect due to the reactive oxygen species (ROS) production under LED irradiation. The work not only provides a facile method for the preparation of antibacterial composite but develops a valuable strategy to the visible light-induced antibacterial agent.

Carbazole-Pyridazine copolymers and their rhenium complexes: Effect of the molecular structure on the electronic properties

Two new push–pull copolymers, poly[N-(9-heptadecanyl)carbazole-2,7-diyl-alt-phthalazine- 5,8-diyl] (P1) and poly[N-(9-heptadecanyl)carbazole-2,7-diyl-alt-thieno[3,4-d]pyridazine- 5,7-diyl] (P2), were synthetized by means of a Suzuki polycondensation. The molecular characterization with 1H NMR and MALDI-MS showed enchainment defects in the polymer backbones depending on the synthetic conditions (catalyst and temperature). Both carbazole-carbazole and diazine-diazine homocoupling defects occurred, particularly in the case of P2. For P1, instead, almost homocoupling-free material was obtained. Exploiting the metal coordination capability of the pyridazine ring, corresponding dinuclear rhenium-based metallopolymers, ReP1 and ReP2, were also synthetized. All materials were investigated with experimental techniques (UV–vis spectroscopy, photoluminescence, cyclic voltammetry) and corroborated by theoretical studies (DFT and TD-DFT), including a qualitative evaluation of the effects of backbone defects on the electronic properties of the polymers. They were also tested in organic photovoltaic (OPV) devices. The wide energy gaps (Eg) accompanied with a low absorption coefficient for the band in the visible range reduced the harvesting capability of the copolymers. These drawbacks were partially overcome in the metallopolymers. The low device performance was mainly attributable to the low solubility of the metallopolymers in the organic solvents.

Absorption Performance of Doped TiO2-Based Perovskite Solar Cell using FDTD Simulation

In the third generation of the solar cell era, significant trends in the development of perovskite solar cells (PSC) were observed. Exploring suitable materials for its wafer structure, such as perovskite and electron transport layers (ETL), were a major emphasis of high-performance PSC development. Because of its matching band structure to MaPbI3, TiO2 is the most often utilized material for ETL. However, in the application of TiO2 to PSC, electron trapping and a wide energy gap become a drawback. The goal of this research is to improve the absorption performance of PSC employing ETL with Fe and Ta-doped TiO2 as well as the thickness of the material. The interaction between the electromagnetic waves of light and the solar cell structure was calculated using Finite-Difference Time-Domain (FDTD) simulations, which resulted in the absorption spectra. In comparison to pure TiO2, which absorbs only 79.5% of the incident light, Fe-TiO2 and Ta-TiO2 as ETL in solar cells have increased absorption spectra to 81.7% and 81.2%, respectively. Finally, we may conclude that the optimum ETL layer parameters are 0.32% Fe doping and a thickness of 100 nm.

Temperature sensing performance of ScVO4: Eu3+ phosphors by employing ground state thermal coupling approach

Lanthanides doped vanadate luminescence materials have gained a lot of attention for their use in non-contact optical thermometry, because of the advantages of non-intrusive and real-time temperature detection. The approach of fluorescence intensity ratio (FIR) of two thermally coupled excited states is the most promising approach but their performance in a lower temperature range is limited due to thermal decoupling among the two emitting levels with a wide energy gap. Thus, in this work, the temperature sensing ability of ScVO4:2% Eu3+ phosphor synthesized successfully through a high-temperature solid-state reaction has been explored by employing the ground state thermal coupling approach. Various experimental and theoretical approaches were used to check the structure and compositional stability of the synthesized ScVO4:2%Eu3+ phosphors host lattice. The temperature-dependent emission intensity of 5D0→7F4 has been measured under 616.3 nm excitation corresponding to 5D0→7F2 absorption, which shows the remarkable increasing behavior with rising of temperature ranging from 113 K to 323 K. The highest value of the relative sensitivity reached 7.19% K−1 at 113 K which is higher than previously reported materials. The obtained results reveal that ScVO4:2% Eu3+ phosphor is a promising candidate for non-contact optical thermometry.

Strong correlation effects in vanadium oxide films

In the present work the metal-insulator transition in doubly orbitally degenerated model of quasi-two-dimensional material based on V2O3 film, in which a crucial role is played by on-site Coulomb interaction and correlated hopping of electrons, has been investigated. With use of a projection procedure in the Green function method the energy spectrum of electrons has been calculated to model variations of the material properties at the temperature changes, the external pressure application and doping. The obtained expressions for thermodynamic potential and the energy gap widths allow analyzing the possible phase transitions in a system, the dependency of characteristics on the external actions for this strongly correlated material.