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Pressure-induced phase transition in transition metal trifluorides

Chinese Physics B 2022年第10期31卷 102-106页

作者： Peng Liu Meiling Xu Jian Lv Pengyue Gao Chengxi Huang Yinwei Li Jianyun Wang Yanchao Wang Mi Zhou State Key Laboratory of Superhard Materials&International Center for Computational Method and Software College of PhysicsJilin UniversityChangchun 130012China Laboratory of Quantum Functional Materials Design and Application School of Physics and Electronic EngineeringJiangsu Normal UniversityXuzhou 221116China MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing Nanjing University of Science and TechnologyNanjing 210094China

As a fundamental thermodynamic variable, pressure can alter the bonding patterns and drive phase transitions leading to the creation of new high-pressure phases with exotic properties that are inaccessible at ambient pressure. Using the swarm intelligence structural prediction method, the phase transition of TiF_(3), from R-3c to the Pnma phase, was predicted at high pressure, accompanied by the destruction of TiF_6 octahedra and formation of TiF_8 square antiprismatic units. The Pnma phase of TiF_(3), formed using the laser-heated diamond-anvil-cell technique was confirmed via high-pressure x-ray diffraction experiments. Furthermore, the in situ electrical measurements indicate that the newly found Pnma phase has a semiconducting character, which is also consistent with the electronic band structure calculations. Finally, it was shown that this pressure-induced phase transition is a general phenomenon in ScF_(3), VF_(3), CrF_(3), and MnF_(3), offering valuable insights into the high-pressure phases of transition metal trifluorides.

关键词： high-pressure structure transition crystal structure prediction high-pressure x-ray diffraction experiments transition metal

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Optimizing the n-type carrier concentration of an InVO4 photocatalyst by codoping with donors and intrinsic defects

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Physical Review Applied 2024年第4期22卷 044047页

作者： Aodi Zhang Hang Li Hongbin Xu Baoying Dou Genqiang Zhang Wentao Wang School of Physics and Electronics Guizhou Provincial Key Laboratory of Computational Nano-Material Science School of Physics and Electron Science Henan Key Laboratory of Quantum Materials and Quantum Energy School of Future Technology CAS Key Laboratory of Materials for Energy Conversion Department of Materials Science and Engineering

Although indium vanadate (InVO4) is an excellent n-type semiconductor, a controlled n-type carrier concentration of the InVO4 photocatalyst is required to enhance its photocatalytic activity. This study systematically explores the self-consistent Fermi energies, dominant intrinsic defects, electron concentration (n0), and defect concentration of InVO4 using density-functional theory coupled with detailed thermodynamic equilibrium simulations. The results indicate that the VIn antisite defect (the vanadium atom replacing the indium atom) is the dominant intrinsic defect in InVO4. The calculated Fermi energy pinning position indicates that InVO4 has n-type doping behavior from intrinsic defects under O-poor growth conditions, consistent with the experiments. Interestingly, donor (D+) doping is positive for improving the n0 of the intrinsic-defect-doped InVO4. Therefore, at 300 K, a broad optimized chemical potential region (OCPR) is obtained for InVO4 codoped with donors and intrinsic defects. In this OCPR, the n0 is higher, without recombination centers and significant compensation, significantly enhancing the photocatalytic activity of InVO4. However, for the case of growth temperature at 873 K and after quenching from 873 to 300 K, the OCPR is much narrower than that at 300 K, indicating that higher temperatures may adversely affect the OCPR. Our results provide deep insights into defect behaviors in InVO4 and suggest strategies for enhancing its n-type conductivity properties, offering new opportunities for manipulating the photocatalytic performance of InVO4.

关键词： Carrier generation & recombination Doping effects Photocatalysis Point defects 3-dimensional systems Doped semiconductors Transition metal oxides Density functional calculations

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Single-atom catalysts based on two-dimensional metalloporphyrin monolayers for ammonia synthesis under ambient conditions

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Nano Research 2022年第5期15卷 4039-4047页

作者： Chun-Xiang Huang Sheng-Yao Lv Cong Li Bin Peng Guoliang Li Li-Ming Yang Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Key Laboratory of Material Chemistry for Energy Conversion and StorageMinistry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Theoretical Chemistry of Environment Ministry of EducationCenter for Computational Quantum ChemistrySchool of ChemistrySouth China Normal UniversityGuangzhou 510006China

We systematically investigated the catalytic performance of 3d,4d,and 5d transition metals anchored onto two-dimensional extended porphyrin(PP)substrates as nitrogen reduction reaction(NRR)electrocatalysts,employing density functional theory(DFT)calculations and four-step high-throughput *** novel metalloporphyrin(MPP,M=Zr,Nb,Hf,and Re)single-atom catalyst candidates have been identified due to their excellent catalytic performance(low onset potential,high stability,and selectivity).Through comprehensive reaction path search,the maximum Gibbs free energy changes for NRR on the ZrPP(enzymatic-consecutive hybrid path),NbPP(consecutive path),HfPP(enzymatic-consecutive hybrid path),and RePP(distal path)catalysts are 0.38,0.41,0.53,and 0.53 eV,*** structures,projected density of states,and charge/spin distributions show that the high catalytic activity is due to significant orbital hybridizations and charge transfer between N_(2) and MPP *** hope our work will promote experimental synthesis of these NRR electrocatalysts and provide new opportunities to the electrochemical conversion of N_(2) to NH_(3) under ambient conditions.

关键词： electrocatalytic nitrogen reduction reaction two-dimensional(2D)extended metalloporphyrin(MPP)monolayer singleatom catalyst two-dimensional materials high-throughput screening first-principles calculations

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Unveiling the Underlying Mechanism of Transition Metal Atoms Anchored Square Tetracyanoquinodimethane Monolayers as Electrocatalysts for N_(2) Fixation

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Energy & Environmental materials 2022年第2期5卷 533-542页

作者： Shengyao Lv Chunxiang Huang Guoliang Li Liming Yang Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Key Laboratory of Material Chemistry for Energy Conversion and StorageMinistry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Theoretical Chemistry of Environment Ministry of EducationCenter for Computational Quantum ChemistrySchool of ChemistrySouth China Normal UniversityGuangzhou 510006China

We for the first time systematically studied the structures and electrochemical nitrogen reduction reaction properties of two-dimensional single transition-metal anchored square tetracyanoquinodimethane monolayers(labeled as:TM-sTCNQ,TM=3d,4d,5d series transition metals)by employing density functional theory *** highthroughput screenings and full reaction path researches,two promising electrochemical nitrogen reduction reaction catalysts Nb-sTCNQ and MosTCNQ have been *** nitrogen reduction reaction onset potential on Nb-sTCNQ is as low as−0.48 ***,the Nb-sTCNQ catalyst can quickly desorb NH3 produced with a free energy of 0.65 eV,giving Nb-sTCNQ excellent catalytic cycle *** high catalytic activity of the two materials might be attributed to the effective charge transfer between the active center and adsorbed N_(2),which enables the active center to adsorb and activate inert N_(2) molecules well,and the reduction processes require small energy input(i.e.,the maximum free energy changes are small).This work provides insights for finding highly efficient,stable,and low-cost nitrogen reduction reaction *** hope our results can promote further experimental and theoretical research of this field.

关键词： 2D TM-sTCNQ monolayers density functional theory method electrochemical nitrogen reduction reaction high-throughput screening single-atom catalysts

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Fe single atom trigger asymmetric In-In polarized site pairs boosting near-infrared N2 photoreduction

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materials Today 2025年 86卷 96-103页

作者： Liang, Huimin Ye, Caichao Wu, Yao Li, Yezi Long, Ran Xiong, Jun Jiang, Wei Di, Jun School of Chemistry and Chemical Engineering National Special Superfine Powder Engineering Research Center Nanjing University of Science and Technology Nanjing210094 China Academy for Advanced Interdisciplinary Studies & Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen518055 China School of Materials Science & Engineering Nanyang Technological University Singapore639798 Singapore National Synchrotron Radiation Laboratory CAS Center for Excellence in Nanoscience School of Chemistry and Materials Science University of Science and Technology of China Hefei230026 China Institute for Energy Research Jiangsu University Zhenjiang212013 China

Building differentiated charge distributed polarized atomic pairs may be an alternative for N2 activation. In this work, CuInS2 atomic layers with asymmetric In-In polarized site pairs are prepared by doping Fe single atoms, as proved by X-ray absorption fine structure spectroscopy, quasi in situ X-ray photoelectron spectra and calculated atomic charge distribution. The engineered Fe single atoms tuned the surface atomic charge distribution, building local polarization center to boost directional surface charge separation. The formed In-In polarized site pairs with asymmetric charge distribution creates distinct interaction with two N atoms in N2 molecule, contributing to the enhanced activation of N2. The alternating pathway is regarded as hydrogenation pathway over Fe-CuInS2 with *NNH formation as rate-determining step. The charge-redistributed surface atomic structure after engineered Fe single atoms strengthens intermediate interaction and lower the rate-determining step energy barrier. Benefiting from these features, Fe-CuInS2 exhibits excellent photocatalytic activity under near-infrared (NIR) irradiation with an ammonia synthesis rate of 94.1 μmol g−1 h−1. In comparison, the N2-NH3 conversion rate of Fe-CuInS2 under ultraviolet–visible (UV–Vis) irradiation could reach 137.4 μmol g−1 h−1, which is about 6.8 times higher than that of CuInS2. The apparent quantum efficiencies of Fe-CuInS2-2 at 380, 400, 450, 500, 550, 650, 700, 800, 850 and 1064 nm were 3.0 %, 3.3 %, 2.7 %, 2.1 %, 2.0 %, 1.5 %, 1.3 %, 0.4 %, 0.7 % and 0.6 %, respectively. © 2025 Elsevier Ltd

关键词： X ray absorption fine structure spectroscopy

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Boosting the intrinsic anomalous Hall effect through a topological phase transition in the magnetic Weyl semimetal Co3Sn2S2

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Physical Review B 2023年第20期107卷 205138-205138页

作者： Hongyi Sun Qihang Liu Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology Shenzhen 518055 China International Quantum Academy Shenzhen 518048 China Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen 518055 China Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen 518055 China

The anomalous Hall Effect (AHE) is one of the most fundamental phenomena related to band topology and holds great potential for technological applications. A promising approach to search for large AHE is to begin with a magnetic Weyl semimetal (WSM) and manipulate the Weyl nodes in the momentum-energy (k−E) space. However, controlling the Weyl points is generally difficult because Weyl nodes can robustly exist at a generic momentum. Here we realize this approach in an experimentally confirmed ferromagnetic WSM Co3Sn2S2 via tension. Our calculations systematically demonstrate that the tension applied to Co3Sn2S2 can drive the movement and annihilation of Weyl nodes in the k−E space, triggering a high-Chern-number three-dimensional quantum AHE topological phase transition and thus greatly boosting the AHE. We also found a rare way of annihilation of Weyl nodes occurring near the Brillouin zone boundary. Our work offers a promising way to boost the AHE and sheds light on the search for three-dimensional quantum anomalous Hall insulators.

关键词： Anomalous Hall effect First-principles calculations quantum anomalous Hall effect Topological materials Topological phase transition

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Direct Synthesis of Layer-Tunable and Transfer-Free Graphene on Device-Compatible Substrates Using Ion Implantation Toward Versatile Applications

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Energy & Environmental materials 2024年第5期7卷 408-418页

作者： Bingkun Wang Jun Jiang Kevin Baldwin Huijuan Wu Li Zheng Mingming Gong Xuehai Ju Gang Wang Caichao Ye Yongqiang Wang Department of Microelectronic Science and Engineering School of Physical Science and TechnologyNingbo UniversityNingbo 315211China Key Laboratory of Soft Chemistry and Functional Materials of MOE School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Center for Integrated Nanotechnologies Los Alamos National LaboratoryLos Alamos 87545New MexicoUSA National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China Academy for Advanced Interdisciplinary Studies&Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and TechnologyShenzhen 518055China Materials Science and Technology Division Los Alamos National LaboratoryLos Alamos 87545New MexicoUSA

Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device *** of the art in the field is currently a two-step process:a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition(CVD)followed by delicate layer transfer onto device-relevant ***,we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area,high quality,and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer ***(C)ion implantation was performed on Cu-Ni film deposited on a variety of device-relevant substrates.A well-controlled number of layers of graphene,primarily monolayer and bilayer,is precisely controlled by the equivalent fluence of the implanted C-atoms(1 monolayer~4×10^(15)C-atoms/cm^(2)).Upon thermal annealing to promote Cu-Ni alloying,the pre-implanted C-atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C-solubility in *** a result,the expelled C-atoms precipitate into a graphene structure at the interface facilitated by the Cu-like alloy *** removing the alloyed Cu-like surface layer,the layer-tunable graphene on the desired substrate is directly *** layer-selectivity,high quality,and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene *** dynamics(MD)simulations using the reactive force field(ReaxFF)were performed to elucidate the graphene formation mechanisms in this novel synthesis *** the wide use of ion

关键词： device applications dual-metal smart Janus substrate growth mechanism Ion implantation layer-tunable and transfer-free graphene

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Fifth-Order A-WENO Path-Conservative Central-Upwind Scheme for Behavioral Non-Equilibrium Traffic Models

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Communications in computational Physics 2023年第3期33卷 692-732页

作者： Shaoshuai Chu Alexander Kurganov Saeed Mohammadian Zuduo Zheng Department of Mathematics Southern University of Science and TechnologyShenzhen518055P.R.China Shenzhen International Center for Mathematics and Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and TechnologyShenzhen518055P.R.China School of Civil Engineering the University of QueenslandBrisbane Qld4072Australia.

Non-equilibrium hyperbolic traffic models can be derived as continuum approximations of car-following models and in many cases the resulting continuum models are *** leads to numerical difficulties,which seem to have discouraged further development of complex behavioral continuum models,which is a significant research *** this paper,we develop a robust numerical scheme that solves hyperbolic traffic flow models based on their non-conservative *** develop a fifth-order alternative weighted essentially non-oscillatory(A-WENO)finite-difference scheme based on the path-conservative central-upwind(PCCU)method for several non-equilibrium traffic flow *** order to treat the non-conservative product terms,we use a path-conservative *** this end,we first apply the recently proposed secondorder finite-volume PCCU scheme to the traffic flow models,and then extend this scheme to the fifth-order of accuracy via the finite-difference A-WENO *** designed schemes are applied to three different traffic flow models and tested on a number of challenging numerical *** schemes produce quite accurate results though the resolution achieved by the fifth-order A-WENO scheme is *** proposed scheme in this paper sets the stage for developing more robust and complex continuum traffic flow models with respect to human psychological factors.

关键词： Finite-difference A-WENO schemes finite-volume central-upwind schemes pathconservative central-upwind schemes non-oscillatory schemes continuum traffic flow model driver behavior.

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Machine learning assisted discovering of new M_(2)X_(3)-type thermoelectric materials

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Rare Metals 2022年第5期41卷 1543-1553页

作者： Du Chen Feng Jiang Liang Fang Yong-Bin Zhu Cai-Chao Ye Wei-Shu Liu Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China Department of Physics & Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and TechnologyShenzhen 518055China Key Laboratory of Energy Conversion and Storage Technologies(Ministry of Education) Southern University of Science and TechnologyShenzhen 518055China

Recent years have witnessed a continuous discovering of new thermoelectric materials which has experienced a paradigm shift from try-and-error efforts to experience-based discovering and first-principles calculation. However, both the experiment and first-principles calculation deriving routes to determine a new compound are time and resources consuming. Here, we demonstrated a machine learning approach to discover new M_(2)X_(3)-type thermoelectric materials with only the composition information. According to the classic Bi_(2)Te_(3) material, we constructed an M_(2)X_(3)-type thermoelectric material library with 720 compounds by using isoelectronic substitution, in which only 101 compounds have crystalline structure information in the Inorganic Crystal Structure Database(ICSD) and materials Project(MP) database. A model based on the random forest(RF) algorithm plus Bayesian optimization was used to explore the underlying principles to determine the crystal structures from the known compounds. The physical properties of constituent elements(such as atomic mass, electronegativity, ionic radius) were used to define the feature of the compounds with a general formula ^(1)M^(2)M^(1)X^(2)X^(3)X(^(1)M +^(2)M:^(1)X +^(2)X+^(3)X = 2:3). The primary goal is to find new thermoelectric materials with the same rhombohedral structure as Bi_(2)Te_(3) by machine *** final trained RF model showed a high accuracy of 91% on the prediction of rhombohedral compounds. Finally, we selected four important features to proceed with the polynomial fitting with the prediction results from the RF model and used the acquired polynomial function to make further discoveries outside the pre-defined material library.

关键词： Thermoelectric materials M_(2)X_(3)-type material library Random forest(RF)algorithm Bayesian optimization Machine learning

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A direct measurement method of quantum relaxation time

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National Science Review 2021年第4期8卷 91-99页

作者： Peng Zhang Haoqi Tang Chuanchuan Gu Hong Wang Guangfu Luo Yalin Lu X.-D.Xiang Department of Materials Science and Engineering & Department of Physics Southern University of Science and Technology Synergetic Innovation Center of Quantum Information and Quantum Physics & Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Materials Genome Initiative Center and School of Materials Science and Engineering Shanghai Jiao Tong University State Key Laboratory of Green Building Materials China Building Materials Academy Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology

The quantum relaxation time of electrons in condensed matters is an important physical property, but its direct measurement has been elusive for a century. Here, we report a breakthrough that allows direct determination of quantum relaxation time at zero and non-zero frequencies using optical *** dielectric loss function, we connect bound electron effects to the physical parameters of plasma resonance and find an extra term of quantum relaxation time from inelastic scattering between bound electrons and conduction electrons at non-zero frequencies. We demonstrate here that the frequency-dependent inelastic polarization effect of bound electrons is the dominant contribution to quantum relaxation time of conduction electrons at optical frequencies, and the elastic polarization effect of bound electrons also dramatically changes the plasma resonance frequency through effective screening to charge carriers.

关键词： quantum relaxation time plasma resonance dielectric loss function

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