期刊：
Journal of Physics Condensed Matter,1997年9(8):L105-L110 ISSN：0953-8984
通讯作者：
Zhong, J.X.
作者机构：
[Zhong, J.X. ] Xiangtan Univ, Hunan, China
关键词：
Harper model - Inverse power law - Level spacing distribution - Metal insulator transitions - Quasiperiodic systems
摘要：
Energy-level statistics in a quasiperiodic system possessing a metal-insulator transition is investigated. For this purpose, the integrated level-spacing distribution I(s) for the Harper model with an incommensurate potential u<inf>i</inf> = λcos(2πσi) is numerically calculated. It is shown that there are only three possible distributions. In the metallic regime λ<2, I(s) is of the form (2/π) cos<sup>-1</sup> (2As/π), where A is a constant. In the insulating regime λ>2, I(s) follows the same law as it does in the situation where the energy levels are equal to u<inf>i</inf>. At the critical point λ= 2, I(s) is described by an inverse power law I(s) approx. s<sup>-β</sup> with β= 1/2 . The derivative of I(s) indicates that level-spacing distributions for the Harper model in the metallic and insulator regimes are different from the well known Wigner surmise and Poisson law for disordered systems.
通讯机构：
[Qi, X] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.
摘要：
We have studied the stable geometries, band structures and magnetic properties of transition-metal (V, Cr, Mn, Fe, Co and Ni) atoms absorbed on MoS2/h-BN heterostructure systems by first-principles calculations. By comparing the adsorption energies, we find that the adsorbed transition metal (TM) atoms prefer to stay on the top of Mo atoms. The results of the band structure without spin-orbit coupling (SOC) interaction indicate that the Cr-absorbed systems behave in a similar manner to metals, and the Co-absorbed system exhibits a half-metallic state. We also deduce that the V-, Mn-, Fe-absorbed systems are semiconductors with 100% spin polarization at the HOMO level. The Ni-absorbed system is a nonmagnetic semiconductor. In contrast, the Co-absorbed system exhibits metallic state, and the bandgap of V-absorbed system decreases slightly according to the SOC calculations. In addition, the magnetic moments of all the six TM atoms absorbed on the MoS2/h-BN heterostructure systems decrease when compared with those of their free-standing states.
通讯机构：
[Huang, ZY] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
A novel binder-free electrode material of NiMoO4@CoMoO4 hierarchical nanospheres anchored on nickel foam with excellent electrochemical performance has been synthesized via a facile hydrothermal strategy. Microstructures and morphologies of samples are characterized by X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Besides, the effect of Ni/Co molar ratios of raw materials on electrochemical behaviors is also investigated by cyclic voltammetry, galvanostatic charge-discharge measurements, cycling tests and electrochemical impedance spectroscopy methods. Remarkably, the resulting NiMoO4@CoMoO4 hierarchical nanospheres with a Ni/Co molar ratio of 4 :1 exhibit greatly enhanced capacitive properties relative to other components and display a high specific capacitance of 1601.6 F g(-1) at the current density of 2 A g(-1), as well as better cycling stability and rate capability. Moreover, a symmetric supercapacitor is constructed using NiMoO4@CoMoO4 nanospheres as the positive and negative electrodes with one piece of cellulose paper as the separator, which shows good electrochemical performance. Such enchanced capacitive properties are mostly attributed to the synergistic effect of nickel and cobalt molybdates directly deposited on the conductive substrate and their novel hierarchical structure, which can provide pathways for fast diffusion and transportation of ions and electrons and a large number of active sites. The results imply that the NiMoO4@CoMoO4 hierarchical nanospheres could be promising candidates for electrochemical energy storage.
作者：
Shi, Xizhi;He, Chaoyu;Pickard, Chris J.;Tang, Chao;Zhong, Jianxin
期刊：
PHYSICAL REVIEW B,2018年97(1) ISSN：2469-9950
通讯作者：
He, CY
作者机构：
[Tang, Chao; He, Chaoyu; Shi, Xizhi; Zhong, Jianxin] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Tang, Chao; He, Chaoyu; Shi, Xizhi; Zhong, Jianxin] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Peoples R China.;[Pickard, Chris J.] Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England.;[Pickard, Chris J.] Tohoku Univ, Adv Inst Mat Res, Aoba Ku, 2-1-1 Katahira, Sendai, Miyagi 9808577, Japan.
通讯机构：
[He, CY] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Peoples R China.;Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
A method is introduced to stochastically generate crystal structures with defined structural characteristics. Reasonable quotient graphs for symmetric crystals are constructed using a random strategy combined with space group and graph theory. Our algorithm enables the search for large-size and complex crystal structures with a specified connectivity, such as threefold sp2 carbons, fourfold sp3 carbons, as well as mixed sp2-sp3 carbons. To demonstrate the method, we randomly construct initial structures adhering to space groups from 75 to 230 and a range of lattice constants, and we identify 281 new sp3 carbon crystals. First-principles optimization of these structures show that most of them are dynamically and mechanically stable and are energetically comparable to those previously proposed. Some of the newstructures can be considered as candidates to explain the experimental cold compression of graphite.
作者：
Liu, Wenliang;Peng, Xiangyang;Wei, Xiaolin;Yang, Hong;Stocks, G. Malcolm;Zhong, Jianxin
期刊：
PHYSICAL REVIEW B,2013年87(20) ISSN：1098-0121
通讯作者：
Liu, WL
作者机构：
[Stocks, G. Malcolm] Oak Ridge Natl Lab, Mat Sci & Technol Div, Oak Ridge, TN 37831 USA.;[Wei, Xiaolin; Zhong, Jianxin; Peng, Xiangyang; Yang, Hong; Liu, Wenliang] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Wei, Xiaolin; Zhong, Jianxin; Peng, Xiangyang; Yang, Hong; Liu, Wenliang] Xiangtan Univ, Fac Mat & Optoelect Phys, Lab Quantum Engn & Micro Nano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
通讯机构：
[Liu, WL] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Based on van der Waals density functional calculations, we have studied few-quintuple-layer (QL) films of Bi2Se3 and Bi2Te3. The separation between the QLs near the surface is found to have a large increase after relaxation, whereas, the separation between the inner QLs is smaller and approaches the bulk value as the thickness grows, showing a two-dimensional to three-dimensional structural crossover. Accordingly, the surface Dirac cone of the Bi2Se3 film is evidently gapped for small thicknesses (two to four QLs), and the gap is reduced and, finally, is closed with the increasing thickness, agreeing well with the experiments. We further studied the substrate effect by investigating the Bi2Se3/graphene system. It is found that the underlying graphene induces a giant thickness-dependent Rashba splitting and Dirac point shift. Because Bi2Te3 films have smaller relative inter-QL expansion and stronger spin-orbit coupling, the topological features start to appear in the film as thin as two QLs in good accord with the experiments.
作者机构：
[Stocks, G. Malcolm; Zhu, Wenguang; Xiao, Di] Oak Ridge Natl Lab, Div Mat Sci & Technol, Oak Ridge, TN 37831 USA.;[Wei, Xiaolin; Zhong, Jianxin; Peng, Xiangyang; Yang, Hong; Liu, Wenliang] Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Wei, Xiaolin; Zhong, Jianxin; Peng, Xiangyang; Yang, Hong; Liu, Wenliang] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.;[Wei, Xiaolin; Zhong, Jianxin; Peng, Xiangyang; Yang, Hong; Liu, Wenliang] Xiangtan Univ, Fac Mat & Optoelect Phys, Xiangtan 411105, Hunan, Peoples R China.;[Yang, Hong] Jishou Univ, Dept Phys, Jishou 416000, Hunan, Peoples R China.
通讯机构：
[Yang, H] Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Based on first-principles calculations within density functional theory, we find that Pb adlayers can induce a giant Rashba spin splitting in the quantum well states of an underlying Bi2Se3 film. As the thickness of the Pb adlayers varies, the distance between the Pb adlayer and the Bi2Se3 film, the charge density at the interface, and the binding between the Pb adlayers exhibit an oscillatory behavior due to the quantum size effects, which in turn modulates the magnitude of the Rashba spin splitting of the quantum well states in the Bi2Se3 film.
作者机构：
[Liu, Li-Min] Beijing Computat Sci Res Ctr, Lab Green Energy, Beijing 100084, Peoples R China.;[Wei, Xiaolin; Xie, Yuee; Ouyang, Tao; Zhong, Jianxin; Chen, Yuanping] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
通讯机构：
[Ouyang, T] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Graphyne, a new allotrope of carbon, is a current topic of focus in the nanomaterial research community. We investigate the thermal transport property of graphyne nanoribbons (GYNRs) by using the nonequilibrium Green's-function method. The thermal conductance of GYNRs is only approximately 40% that of graphene nanoribbons. A distinct width dependence of the thermal property is observed in GYNRs as well. The conductance of armchair-edged GYNRs (A-GYNRs) shows a linear width dependence, while a steplike width dependence is displayed in the conductance of zigzag-edged GYNRs (Z-GYNRs). Moreover, the conductance of an A-GYNR is larger than that of a Z-GYNR of the same width, indicating obvious anisotropic transport in graphyne (twice that in graphene). In addition, the thermal transport in graphyne family nanoribbons is also explored. The results show that the conductance of graphyne family nanoribbons is insensitive to the acetylenic linkages, but depends on the number of benzene rings. These findings could offer useful guidelines for the design and performance improvement of the graphyne-based nanodevices.
作者：
Ren, Long;Hui, K. N.;Hui, K. S.;Liu, Yundan;Qi, Xiang;Zhong, Jianxin;Du, Yi;Yang, Jianping
期刊：
SCIENTIFIC REPORTS,2015年5 ISSN：2045-2322
通讯作者：
Ren, L
作者机构：
[Du, Yi; Yang, Jianping; Ren, Long] Univ Wollongong, Australian Inst Innovat Mat, Inst Superconducting & Elect Mat, North Wollongong, NSW 2500, Australia.;[Zhong, Jianxin; Ren, Long; Qi, Xiang; Liu, Yundan] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Zhong, Jianxin; Ren, Long; Qi, Xiang; Liu, Yundan] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;[Yang, Jianping] Tongji Univ, State Key Lab Pollut Control & Resources Reuse, Coll Environm Sci & Engn, Shanghai 200092, Peoples R China.;[Hui, K. S.] Hanyang Univ, Dept Mech Convergence Engn, Seoul 133791, South Korea.
通讯机构：
[Ren, L] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
New and novel 3D hierarchical porous graphene aerogels (HPGA) with uniform and tunable mesopores (e.g., 21 and 53 nm) on graphene nanosheets (GNS) were prepared by a hydrothermal self-assembly process and an in-situ carbothermal reaction. The size and distribution of the meso-pores on the individual GNS were uniform and could be tuned by controlling the sizes of the Co3O4 NPs used in the hydrothermal reaction. This unique architecture of HPGA prevents the stacking of GNS and promises more electrochemically active sites that enhance the electrochemical storage level significantly. HPGA, as a lithium-ion battery anode, exhibited superior electrochemical performance, including a high reversible specific capacity of 1100 mAh/g at a current density of 0.1 A/g, outstanding cycling stability and excellent rate performance. Even at a large current density of 20 A/g, the reversible capacity was retained at 300 mAh/g, which is larger than that of most porous carbon-based anodes reported, suggesting it to be a promising candidate for energy storage. The proposed 3D HPGA is expected to provide an important platform that can promote the development of 3D topological porous systems in a range of energy storage and generation fields.
通讯机构：
[Zhong, JX] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
摘要：
We successfully developed a simple electrophoretic deposition (EPD) method to decorate the MoSe2 nanosheets on the carbon fiber surface of carbon cloth (MoSe2/CC). With this process, MoSe2 nanosheets can be uniformly and tightly deposited on this flexible conductor to form a 3D binder-free electrode for hydrogen evolution reaction (HER). The film thickness can also be controlled by the EPD time. Directly used as binder-free electrodes for hydrogen evolution reaction, the as-prepared 3D MoSe2/CC samples exhibit excellent catalytic activity in an acidic electrolyte (21 mA/cm(2) at an overpotential of 250 mV). Variation of MoSe2 nanosheets film thickness in the electrodes could affect the catalytic activity, and it was found that the MoSe2/CC sample prepared with 60 min EPD time shows the highest HER activity amongst these different thickness samples. Moreover, stability tests though long-term potential cycles (no degradation after 1000 continuous potential cycles) and extended electrolysis confirm the exceptional durability of the catalyst. This development offers us an attractive and active 3D electrode for electrochemical water splitting.
通讯机构：
[Tang, C] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Based on the crystal structures of the previously proposed low energy eta-P and theta-P, five new phosphorene allotropes were predicted through gene segments recombination method. These five new phosphorene allotropes are confirmed dynamically stable and energetically more favorable than their parents (eta-P and theta-P). Especially, the XX-XX type G1-P is confirmed energetically more favorable than most of all the previously proposed phosphorene allotropes, including black phosphorene and blue phosphorene, which is highly expected to be synthesized in future experiment through vapor deposition or epitaxial growth method like blue beta-P. The calculated results also show that such a new promising phosphorene allotrope G1-P is a potential candidate for application in nano-electronics according to its middle band gap of about 1.491 eV from DFT-HSE06 calculation.
通讯机构：
[Tang, C] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Intercalation of hydrogen is important for understanding the decoupling of graphene from SiC(0001) substrate. Employing first-principles calculations, we have systematically studied the decoupling of graphene from SiC surface by H atoms intercalation from graphene boundary. It is found the passivation of H atoms on both graphene edge and SiC substrate is the key factor of the decoupling process. Passivation of graphene edge can weaken the interaction between graphene boundary and the substrate, which reduced the energy barrier significantly for H diffusion into the graphene-SiC interface. As more and more H atoms diffuse into the interface and saturate the Si dangling bonds around the boundary, graphene will detach from substrate. Furthermore, the energy barriers in these processes are relatively low, indicating that these processes can occur under the experimental temperature.
作者机构：
[Stocks, G. Malcolm] Oak Ridge Natl Lab, Mat Sci Technol Div, Oak Ridge, TN 37831 USA.;[Tang, Chao; He, Chaoyu; Wei, Xiaolin; Li, Jin; Zhong, Jianxin; Xiao, Huaping; Meng, Lijun] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Tang, Chao; He, Chaoyu; Wei, Xiaolin; Li, Jin; Zhong, Jianxin; Xiao, Huaping; Meng, Lijun] Xiangtan Univ, Lab Quantum Engn & Micro Nano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.;[Tang, Chao; He, Chaoyu; Wei, Xiaolin; Li, Jin; Zhong, Jianxin; Xiao, Huaping; Meng, Lijun] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;[Kim, Jinwoong; Kioussis, Nicholas] Calif State Univ Northridge, Dept Phys, Northridge, CA 91330 USA.
通讯机构：
[Li, J] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Two-dimensional (2D) topological insulators (TIs) with large band gaps are of great importance for the future applications of quantum spin Hall (QSH) effect. Employing ab initio electronic calculations we propose a novel type of 2D topological insulators, the monolayer (ML) low-buckled (LB) mercury telluride (HgTe) and mercury selenide (HgSe), with tunable band gap. We demonstrate that LB HgTe (HgSe) monolayers undergo a trivial insulator to topological insulator transition under in-plane tensile strain of 2.6% (3.1%) due to the combination of the strain and the spin orbital coupling (SOC) effects. Furthermore, the band gaps can be tuned up to large values (0.2 eV for HgTe and 0.05 eV for HgSe) by tensile strain, which far exceed those of current experimentally realized 2D quantum spin Hall insulators. Our results suggest a new type of material suitable for practical applications of 2D TI at room-temperature.
作者：
Xie, Guofeng;Shen, Yulu;Wei, Xiaolin;Yang, Liwen;Xiao, Huaping;Zhong, Jianxin;Zhang, Gang
期刊：
SCIENTIFIC REPORTS,2014年4 ISSN：2045-2322
通讯作者：
Xie, GF
作者机构：
[Xie, Guofeng; Wei, Xiaolin; Zhong, Jianxin; Yang, Liwen; Shen, Yulu; Xiao, Huaping] Xiangtan Univ, Fac Mat Optoelect & Phys, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;[Zhang, Gang] Inst High Performance Comp, Singapore 138632, Singapore.
通讯机构：
[Xie, GF] Xiangtan Univ, Fac Mat Optoelect & Phys, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.
摘要：
We theoretically investigate the phonon scattering by vacancies, including the impacts of missing mass and linkages (tau(-1)(V)) and the variation of the force constant of bonds associated with vacancies (tau(-1)(A)) by the bond-order-length-strength correlation mechanism. We find that in bulk crystals, the phonon scattering rate due to change of force constant tau(-1)(A) is about three orders of magnitude lower than that due to missing mass and linkages tau(-1)(V). In contrast to the negligible tau(-1)(A) in bulk materials, tau(-1)(A) in two-dimensional materials can be 3-10 folds larger than tau(-1)(V). Incorporating this phonon scattering mechanism to the Boltzmann transport equation derives that the thermal conductivity of vacancy defective graphene is severely reduced even for very low vacancy density. High-frequency phonon contribution to thermal conductivity reduces substantially. Our findings are helpful not only to understand the severe suppression of thermal conductivity by vacancies, but also to manipulate thermal conductivity in two-dimensional materials by phononic engineering.
期刊：
PHYSICAL CHEMISTRY CHEMICAL PHYSICS,2018年20(10):7173-7179 ISSN：1463-9076
通讯作者：
Tang, C
作者机构：
[Tang, Chao; Ouyang, Tao] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Device, Xiangtan 411105, Hunan, Peoples R China.
通讯机构：
[Tang, C] Xiangtan Univ, Hunan Key Lab Micro Nano Energy Mat & Device, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Structure disorder especially edge disorder is unavoidable during the fabrication of nanomaterials. In this paper, using the non-equilibrium Green's function method, we investigate the influence of edge disorder on the thermoelectric performance of gamma(gamma)-graphyne nanoribbons (GYNRs). Our results show that the high Seebeck coefficient in pristine gamma-GYNR could still be preserved although edge disorder is introduced into the structure. Meanwhile, in these edge-disordered nanoribbons the suppression of thermal conductance including electronic and phononic contributions outweighs the reduction of electronic conductance. These two positive effects combine together, and finally boost the thermoelectric conversion efficiency of gamma-GYNRs. The thermoelectric figure of merit ZT in the edge-disordered gamma-GYNRs (the length and width are about 55.68 and 1.41 nm) could approach 2.5 at room temperature, and can even reach as high as 4.0 at 700 K, which is comparable to the efficiency of conventional energy conversion methods. The findings in this paper indicate that the edge-disordered gamma-GYNRs are a promising candidate for efficient thermoelectric energy conversion and thermal management of nanodevices.
通讯机构：
[Sun, LZ] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Peoples R China.
摘要：
Using the first-principles method, we investigate the energetic stability, dynamic stability and electronic properties of two viable three-dimensional (3D) carbon semiconductors with an entirely sp(2) configuration, sp(2)-diamond and cubic-graphite. Both allotropes are more stable than the previously proposed K4-carbon and T-carbon and were confirmed to be dynamically stable. Interestingly, sp(2)-diamond and cubic-graphite behave as semiconductors, which is contrary to previously proposed all-sp(2) metallic carbons. sp(2)-Diamond is a semiconductor with a direct band gap of 1.66 eV and cubic-graphite is an indirect semiconductor with a band gap of 2.89 eV. Further studies show that both sp(2)-diamond and cubic-graphite possess structural all-sp(2) configurations but not electronic sp(2) hybridizations. The very low densities and entirely sp(2) configurations of sp(2)-diamond and cubic-graphite can be potentially applied in hydrogen-storage, photocatalysts and molecular sieves.
通讯机构：
[Zhong, JX] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Peoples R China.
摘要：
In our present work, five previously proposed sp(3) carbon crystals were suggested as silicon allotropes and their stabilities, electronic and optical properties were investigated using the first-principles method. We find that these allotropes with direct or quasi-direct band gaps in a range of 1.2-1.6 eV are very suitable for applications in thin-film solar cells. They display strong adsorption coefficients in the visible range of sunlight in comparison with diamond silicon. These five silicon allotropes are confirmed to possess positive dynamical stability and remarkable themodynamical stability close to that of diamond silicon. In particular, the direct band gap M585-silicon possessing energy higher than diamond silicon only 25 meV per atom is expected to be experimentally produced for thin-film solar cells.
通讯机构：
[Sun, LZ] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Peoples R China.
摘要：
A superhard boron nitride phase dubbed as Z-BN is proposed as a possible intermediate phase between h-BN and zinc blende BN (c-BN), and investigated using first-principles calculations within the framework of density functional theory. Although the structure of Z-BN is similar to that of bct-BN containing four-eight BN rings, it is more energetically favorable than bct-BN. Our study reveals that Z-BN, with a considerable structural stability and high density comparable to c-BN, is a transparent insulator with an indirect band gap of about 5.27 eV. Amazingly, its Vickers hardness is 55.88 GPa which is comparable to that of c-BN. This new BN phase may be produced in experiments through cold compressing AB stacking h-BN due to its low transition pressure point of 3.3 GPa.
通讯机构：
[Sun, LZ] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Peoples R China.
摘要：
Using a generalized genetic algorithm, we propose four new sp(3) carbon allotropes with 5-6-7 (5-6-7-type Z-ACA and Z-CACB) or 4-6-8 (4-6-8-type Z4-A(3)B(1) and A4-A(2)B(2)) carbon rings. Their stability, mechanical and electronic properties are systematically studied using a first-principles method. We find that the four new carbon allotropes show amazing stability in comparison with the carbon phases proposed recently. Both 5-6-7-type Z-ACA and Z-CACB are direct band-gap semiconductors with band gaps of 2.261 eV and 4.196 eV, respectively. However, the 4-6-8-type Z4-A(3)B(1) and A4-A(2)B(2) are indirect band-gap semiconductors with band gaps of 3.105 eV and 3.271 eV, respectively. Their mechanical properties reveal that all the four carbon allotropes proposed in present work are superhard materials, which are comparable to diamond.
作者：
Yao, Hao;Luo, Siwei;Duesberg, Georg S.;Qi, Xiang;Lu, Donglin;Yue, Chao;Zhong, Jianxin
期刊：
AIP ADVANCES,2018年8(7) ISSN：2158-3226
通讯作者：
Zhong, JX
作者机构：
[Lu, Donglin; Luo, Siwei; Zhong, Jianxin; Qi, Xiang; Yue, Chao; Yao, Hao] Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.;[Lu, Donglin; Luo, Siwei; Zhong, Jianxin; Qi, Xiang; Yue, Chao; Yao, Hao] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;[Duesberg, Georg S.; Luo, Siwei] Univ Bundeswehr Munchen, Fac Elect Engn & Informat Technol, Inst Phys, EIT 2, Werner Heisenberg Weg 39, D-85577 Neubiberg, Germany.
通讯机构：
[Zhong, JX] Xiangtan Univ, Sch Phys & Optoelect, Xiangtan 411105, Hunan, Peoples R China.;Xiangtan Univ, Hunan Key Lab Micronano Energy Mat & Devices, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
摘要：
The successful synthesis of large-area SnSe films on SiO2/Si substrate through vapor transport is reported. Based on this we fabricated photodetectors that exhibited a fast response from ultraviolet (UV) to near infrared (NIR) wavelengths. By decorating the SnSe film with graphene oxide quantum dots (GO QDs) the photocurrent and photoresponse time were enhanced significantly over the whole spectrum. Our results indicate that GO functionalised SnSe is a promising material for broadband photodetection. (C) 2018 Author(s).
通讯机构：
[Liu, WL] Xiangtan Univ, Lab Quantum Engn & Micronano Energy Technol, Xiangtan 411105, Hunan, Peoples R China.
摘要：
Based on first-principles calculations, we study the dependence of topological phase on anisotropic interactions in Bi2Se3-type materials. By applying different strains in order to vary interactions, we reveal that the topological phase is insensitive to lateral interaction but can be effectively tuned by longitudinal interaction. Longitudinal strain is inhomogeneous in the studied systems. The interquintuple interaction plays a dominant role in determining the topological phase. We explain the puzzling band-topology difference between Sb2Se3 and Bi2Se3 and propose an approach to tuning the topological phase by strain. It is found that Sb2Se3 can be converted into a topological insulator by applying compressive longitudinal strain while the converse strain can turn Bi2Se3 into a normal insulator. We have studied thin films of Sb2Se3 and Bi2Se3 and also observed a strain-induced topological phase transition.