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Hydrogen reduction characteristics of WO3 based on density functional theory
摘要： The ?rst principle theory in DFT (Density Function Theory) was applied to study the hydrogen adsorption on O-terminated and WO-terminated surface of WO3 (0 0 1). The exploration of the two terminated surfaces structure and hydrogen adsorption characteristics was conducted from the micro-structure point of view. The result indicates that energy of O-terminated surface with enriched oxygen is higher than the WO-terminated surface with less oxygen. The chemical adsorption occurs when the distance between hydrogen molecules and surface atom ranged from 0.6 ? to 0.8 ?, while the physical adsorption occurs when the distance was bigger than 0.8 ?. The energy of hydrogen adsorption on O-terminated surface is lower than energy of hydrogen adsorption on WO-terminated surface, the chemical adsorption of hydrogen is easier to happen compare to physical adsorption. The energy of hydrogen adsorption on O1c on O-terminated surface is lower than energy of hydrogen adsorption on O2c on the same surface. The adsorption of hydrogen not only changes the structure of surfaces of WO3 and cause the conducting electrons jumping into valence band and energy declining but also make a part of electrons in orbit 2p of O to jump into orbit 5p of W.
关键词： Hydrogen adsorption,First principle,Density of states,Reduction,WO3
更新于2025-09-23 15:23:52
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Effect of Au2Cl6 Doping on Stability and Work Function of Graphene
摘要： The first-principles method based on the density functional theory are used to study the work function and stability of the bilayer graphene doped with the Au2Cl6. The results show that the Au2Cl6 interlayer doping, like the common surface doping method, significantly increases the work function of graphene and successfully obtains p-type graphene. In addition, p-type graphene obtained by interlayer doping has better stability than surface doping. Considering the poor stability is a major problem faced in the practical application of surface-doped p-type graphene, this study shows that the interlayer doping of Au2Cl6 is a promising preparation method for p-type graphene.
关键词： first principle,graphene,Au2Cl6 molecule,work function
更新于2025-09-23 15:23:52
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Modulating electronic and magnetic properties of zigzag MoSe2 nanoribbons with different edge structures
摘要： In this paper, we performed the first-principles calculations to investigate the effect of different edge structures on stability, electronic and magnetic properties of zigzag MoSe2 nanoribbons and their corresponding variation by saturating the ribbon edges with H. We have taken twelve patterns of edge structure into consideration due to the chemical nonequivalence of Mo and Se atoms. We found that H-NR-u and H-NR-s have the highest stability by analysing binding energies. Specially, all of the zigzag MoSe2 nanoribbons exhibit obvious metallicity, whether they are hydrogenated or not. What's more, the pristine and hydrogenated zigzag nanoribbons have stable ferrimagnetism with a wide range of total magnetic moment 0.27–3.59 μB. The Mo-terminated nanoribbon has the largest magnetic moment and hydrogenation can significantly reduce the magnetic moment of nanoribbons. We also reveal zigzag MoSe2 nanoribbons with same terminal have very similar stability, electronic and magnetic properties, which have nothing to do with the symmetry of the system. Above all, these unique properties of zigzag MoSe2 nanoribbons have the great potential for electronic, spintronic and magnetoresistive nano-devices in the future.
关键词： Hydrogenation,Nanoribbon,Ferrimagnetism,First-principle calculation,MoSe2
更新于2025-09-23 15:23:52
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Approach to Inversion Design of Dielectric Material Based on the First-Principle
摘要： The ?rst-principle is an e?ective method for the material property calculation. One inversion design idea of dielectric material based on the ?rst-principle was put forward. In this kind of material design thought, the speci?c demanded dielectric property of material is the starting point of the whole design course. The atomic structure characteristic of the material is solved using the inversion model based on the ?rst-principle. And the key issues needing researching were discussed, these problems were quantized structure of electromagnetic and optic ?eld, the quantized polarization theory of dielectric material, the uniform calculation method of dielectric property and the dielectric material inversion model.
关键词： Dielectric material,First-principle,Dielectric property,Inversion design
更新于2025-09-23 15:23:52
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First-principle study on honeycomb fluorated-InTe monolayer with large Rashba spin splitting and direct bandgap
摘要： Rashba e?ect is much related to next-generation spintronic devices. It is highly desirable to search for Rashba materials with large Rashba spin splitting, which is considered as the key factor for the application of spin ?eld-e?ect transistor. Here, we design a two-dimensional monolayer of ?uorated-InTe (InTeF) with large Rashba spin splitting and direct bandgap on the basis of ?rst-principles calculations. InTeF monolayer is energetically and dynamically stable based on the calculations of cohesive energy and phonon dispersion. Remarkably, the Rashba parameter αR is about 1.08 eV·?, comparable to that of the BiTeI monolayer (1.86 eV·?). The direct bandgap is estimated to be 2.48 eV by HSE06 hybrid functional, which shows good prospects in light-emitting devices and photodetectors. To further explore the e?ect of substrates on the electronic structure of InTeF monolayer, we build two heterostructures, and the results show that the strength of Rashba e?ect and the direct bandgap nature in InTeF monolayer can be well preserved under the in?uence of substrates. Based on the above ?ndings in our work, InTeF monolayer is considered to be one of the promising 2D materials for the application of spintronics as well as optoelectronics.
关键词： Rashba spin splitting,InTeF monolayer,First-principle calculation,Direct bandgap
更新于2025-09-23 15:22:29
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Effects of Co Doping and Point Defect on the Ferromagnetism of ZnO
摘要： The effects of different doping proportions of Co doping and oxygen vacancies (VO) on the ferromagnetism of zinc oxide (ZnO) are controversial. To solve this problem, we investigated the effects of Co doping and point defects (VO, VZn, Hi, and Zni) on the ferromagnetism of ZnO through first-principle calculations by using generalized gradient approximation + U (GGA + U) under density functional theory. Results show that the closer the distance between Co and vacancies (VO or VZn), the lower the formation energy and the more stable the system will be. Co-doped ZnO with VO or VZn exhibits long-range ordered ferromagnetism and Curie temperature above the room temperature. Especially, Co-doped ZnO with VZn shows a half-metallic behavior, resulting in 100% conduction hole polarizability, which is highly beneficial for dilute magnetic semiconductors (DMSs) as a hole injection source. The ferromagnetism of Zn14CoO16 is caused by the double exchange effects among the electrons of the O–2p, Co–3d, and Zn–3d orbits mediated by the hole carriers after complexes were formed by the Co doping and Zn vacancy. Similarly, the origin of ferromagnetism in Zn15CoO15 is derived from the double exchange effects among the electrons of O–2p, Co–3d, and Zn–4s states mediated by the electron carriers after complexes were formed by the Co doping and O vacancy. In addition, the result shows that Co-doped ZnO with interstitial H (Hi) or Zn (Zni) is unfavorable for ferromagnetism and should be avoided experimentally.
关键词： First-principle,Co doping and point defect,Ferromagnetism,ZnO
更新于2025-09-23 15:22:29
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High performance and mechanism of the resistive switching device based on lead halide thin films
摘要： In this work, the lead halide was firstly applied in resistive random-access memory (RRAM) device with the structure of W/lead iodide/fluorine-doped tin oxide (FTO). The mechanism was investigated by reliable data fitting and the experiment of temperature influence, illustrating that the resistive switching phenomenon was origin from the filament. The iodide vacancies were considered as the main composition of the conductive filaments, which was verified by the first principle calculation and experimental verification. These performances were also found in device fabricated by other lead halide, such as PbBr2 and PbCl2. Moreover, they performed great potential as the non-volatile memory due to the excellent resistive switching properties. This work was of great significance for the expansion of RRAM material system.
关键词： conductive filaments,lead halide,resistive switching memory,first principle calculation
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Field emission patterns from carbon nanotubes calculated by time-dependent density functional theory
摘要： We calculated the field emission patterns of various types of carbon nanotubes (CNTs). Regarding the near field regime, emission patterns of CNTs and hydrogen terminated CNTs (H-CNTs) well corresponds to the atoms located in the tube tip. We also found different focusing features; a focused-type and an unfocused-type. The beams from armchair (5,5) and (6,6) types are focused, while the beam from zigzag (9,0) types are unfocused.
关键词： field emission,carbon nanotubes,emission pattern,time dependent density functional theory,first principle calculation,ab initio calculation
更新于2025-09-23 15:21:21
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First-principle studies on electron transport properties in four-terminal MoS2 nanoribbons
摘要： We perform the ?rst-principle studies on electron transport through four-terminal MoS2 nanoribbons. It is found that in such structures, insulating bands exist in the linear-conductance spectra of the nanoribbons with straight channels, which are related to the band gaps of the MoS2 nanoribbons. However, nonzero transports are allowed to take place in the insulating-band region in the geometries with curved channels. This phenomenon can be attributed to the formation of edge states in the curved-channel structures. We believe that these results provide useful information for the manipulation of electron transport through MoS2 nanoribbons.
关键词： Electron transport,First-principle studies,MoS2 nanoribbons
更新于2025-09-23 15:21:21
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Improved Electronic Structure and Optical Performance of Bi2Te3-xSex From First-principle Calculations Within TB-mBJ Exchange Potential
摘要： Using the first-principle calculations of density functional theory within the (FP-LAPW) method, we have investigated the structural, electronic and optical properties of Bi2Te3-xSex alloys with compositions x = 0, 1, 2 and 3 of Se. The generalized gradient approximation functional of Wu and Cohen (GGA-PBE) is used to calculate ground state structural parameters of Bi2Te3-xSex , which are in good agreement with theoretical and experimental data. The electronic band structures and optical constants have been improved with Tran-Blaha modified Becker-Johnson (TB-mBJ) parameterization scheme. Also, we have analyzed in detail the performance of dielectric function, refractive index, reflectivity and optical conductivity of these alloys. Our results show that Bi2Te3-xSex alloys are promising candidates for optoelectronic applications especially in the Infrared and visible fields. Bi2Te3-xSex materials have a direct band gap and can be tuned from 0.1706 eV to 0.7819 eV by varying In composition so emission was tunable from 1.58 to 7.26 micrometers (infrared field), in addition for their direct band gap and in view of their attractive optical properties such conductivity, absorption and reflectivity these materials is considered as promising materials for optoelectronic applications.
关键词： Electronic structure,TB-mBJ,Optical properties,First-principle calculations
更新于2025-09-23 15:21:21