检索结果-南通市图书馆

The elphbolt ab initio solver for the coupled electron-phonon Boltzmann transport equations

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 236-244页

作者： Nakib H.Protik Chunhua Li Miguel Pruneda David Broido Pablo Ordejón Catalan Institute of Nanoscience and Nanotechnology(ICN2) CSIC and BISTCampus Bellaterra8193BarcelonaSpain Department of Physics Boston CollegeChestnut HillBostonMA02467USA

elphbolt is a modern Fortran (2018 standard) code for efficiently solving the coupled electron–phonon Boltzmann transport equations from first principles.Using results from density functional and density functional perturbation theory as inputs,it can calculate the effect of the non-equilibrium phonons on the electronic transport (phonon drag) and non-equilibrium electrons on the phononic transport (electron drag) in a fully self-consistent manner and obeying the constraints mandated by thermodynamics.It can calculate the lattice,charge,and thermoelectric transport coefficients for the temperature gradient and electric fields,and the effect of the mutual electron–phonon drag on these transport properties.The code fully exploits the symmetries of the crystal and the transport-active window to allow the sampling of extremely fine electron and phonon wave vector meshes required for accurately capturing the drag phenomena.The coarray feature of modern Fortran,which offers native and convenient support for parallelization,is utilized.The code is compact,readable,well-documented,and extensible by design.

关键词： properties phonon equations

From Elastic Spin to phonon Spin:Symmetry and Fundamental Relations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2022年第12期39卷 41-49页

作者：任捷 Center for phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai 200092China

This work is mainly based on postgraduate lectures at Tongji University since 2020 spring.We firstly revisit the elastic spin and orbital angular momentum[Proc.Natl.Acad.Sci.USA 115,9951(2018)]but more general for anisotropic systems by applying Noether’s theorem to the elastic Lagrangian and by applying the symmetry argument in the field theory.Then,fundamental relations between elastic energy flux and elastic spin are uncovered.In particular cases,the wave spin is closely related to the vorticity of energy flux and momentum.Secondly,we move forward from the elastic spin to revisit the phonon spin[Fizika Tverdogo Tela 3,2160(1961)]by applying the second quantization to elastic fields.We show that the uncovered phonon spin,a polarized elastic-vibration quanta,is generally not restricted to transverse phonon modes,but applying to general phonon modes,such as the longitudinal phonon modes,surface phonon modes,and hybridized phonon modes,regarded as a consequence of mode interferences.The elastic spin and phonon spin originate from the local rotating of the field polarization in time domain,not the local circulation(vorticity)of displacement or velocity in space domain.It is hopeful that the present results could advance the fundamental understanding of phonon spin and elastic spin,and promote the spin phononics for hybrid quantum sensing and technology with multiple degrees of freedom.

关键词： theory phonon applying

phonon anharmonicity:a pertinent review of recent progress and perspective

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2021年第11期64卷 10-43页

作者： Bin Wei Qiyang Sun Chen Li Jiawang Hong Henan Key Laboratory of Materials on Deep-Earth Engineering School of Materials Science and EngineeringHenan Polytechnic UniversityJiaozuo 454000China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Department of Mechanical Engineering University of CaliforniaRiversideRiverside CA 92521USA Materials Science and Engineering University of CaliforniaRiversideRiverside CA 92521USA

Anharmonic lattice vibrations play pivotal roles in the thermal dynamics in condense matters and affect how the atoms interact and conduct heat.An in-depth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is critical for developing better functional and energy materials.In recent years,various novel behaviors in condense matters driven by phonon anharmonic effects were discovered,such as soft mode phase transition,negative thermal expansion(NTE),multiferroicity,ultralow thermal conductivity(κ),high thermal resistance,and high-temperature superconductivity.These properties have endowed anharmonicity with many promising applications and provided remarkable opportunities for developing“Anharmonicity Engineering”-regulating heat transport towards excellent performance in materials.In this work,we review the recent development of studies on phonon anharmonic effect and summarize its origin,mechanism,research methods,and applications.Besides,the remaining challenges,future trends,and prospects of phonon anharmonicity are also discussed.

关键词： phonon phonon anharmonicity thermodynamics inelastic neutron/X-ray scattering

Physics-informed deep learning for solving phonon Boltzmann transport equation with large temperature non-equilibrium

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2022年第1期8卷 245-254页

作者： Ruiyang Li Jian-Xun Wang Eungkyu Lee Tengfei Luo Department of Aerospace and Mechanical Engineering University of Notre DameNotre DameIN46556USA Department of Electronic Engineering Kyung Hee UniversityYongin-siGyeonggi-do17104South Korea Department of Chemical and Biomolecular Engineering University of Notre DameNotre DameIN46556USA Center for Sustainable Energy of Notre Dame(ND Energy) University of Notre DameNotre DameIN46556USA

phonon Boltzmann transport equation(BTE)is a key tool for modeling multiscale phonon transport,which is critical to the thermal management of miniaturized integrated circuits,but assumptions about the system temperatures(i.e.,small temperature gradients)are usually made to ensure that it is computationally tractable.To include the effects of large temperature non-equilibrium,we demonstrate a data-free deep learning scheme,physics-informed neural network(PINN),for solving stationary,mode-resolved phonon BTE with arbitrary temperature gradients.This scheme uses the temperature-dependent phonon relaxation times and learns the solutions in parameterized spaces with both length scale and temperature gradient treated as input variables.Numerical experiments suggest that the proposed PINN can accurately predict phonon transport(from 1D to 3D)under arbitrary temperature gradients.Moreover,the proposed scheme shows great promise in simulating device-level phonon heat conduction efficiently and can be potentially used for thermal design.

关键词： phonon equilibrium equation

"Free-oxygen":A promising functional unit for strengthening electron-phonon coupling effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2023年第3期42卷 4-6页

作者： Fei Liang State Key Laboratory of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan250100China

Electron-phonon coupling is the fundamental physical mechanism for many intriguing cases,such as Jahn-Teller distortion[1],superconductor[2],charge density wave[3],thermoelectric[4],and so on.When electron-phonon coupling effect meets laser,this system would become more interesting with correlated interplay among electron transition,lattice vibrations,as well as stimulated photon emission,thereby trig-gering direct lasing at some unprecedented wavelengths in laser crystals[5].However,due to a few investigations of relationship between electron-phonon coupling and crystal structure,it is difficult to search strongly electron-phonon coupled crystal and extend its lasing wave-lengths consequently.

关键词： coupling phonon lasing

Realizing ultrahigh average figure of merit through manipulating layered phonon-electron decoupling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2022年第7期65卷 1987-1988页

作者： Zizhen Zhou Xiaoyuan Zhou Center of Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China

Developing advanced thermoelectric materials for waste heat recovery is a promising strategy to meet the growing energy demand and low-carbon economy [1].The thermoelectric performance is evaluated by the dimensionles... 详细信息

关键词： ultrahigh Seebeck phonon

How Does van der Waals Confinement Enhance phonon Transport?

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2021年第1期38卷 45-50页

作者：余晓翔马登科邓程程万骁安盟孟涵李小波黄晓明杨诺 State Key Laboratory of Coal Combustion Huazhong University of Science and TechnologyWuhan 430074China School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China NNU-SULI Thermal Energy Research Center(NSTER)&Center for Quantum Transport and Thermal Energy Science(CQTES) School of Physics and TechnologyNanjing Normal UniversityNanjing 210023China College of Mechanical and Electrical Engineering Shaanxi University of Science and TechnologyXi’an 710021China

We study the mechanism of van der Waals(vdW)interactions on phonon transport in atomic scale,which would boost developments in heat management and energy conversion.Commonly,the vdW interactions are regarded as a hindrance in phonon transport.Here we propose that the vdW confinement can enhance phonon transport.Through molecular dynamics simulations,it is realized that the vdW confinement is able to make more than two-fold enhancement on thermal conductivity of both polyethylene single chain and graphene nanoribbon.The quantitative analyses of morphology,local vdW potential energy and dynamical properties are carried out to reveal the underlying physical mechanism.It is found that the confined vdW potential barriers reduce the atomic thermal displacement magnitudes,leading to less phonon scattering and facilitating thermal transport.Our study offers a new strategy to modulate the phonon transport.

关键词： mechanism. phonon dynamical

Managing Quantum Heat Transfer in a Nonequilibrium Qubit-phonon Hybrid System with Coherent phonon States

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2021年第1期38卷 10-18页

作者：王晨王鲁钦任捷 Department of Physics Zhejiang Normal UniversityJinhua 321004China Center for phononics and Thermal Energy Science China-EU Joint Center for NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Sciences and EngineeringTongji UniversityShanghai 200092China

We investigate quantum heat transfer in a nonequilibrium qubit-phonon hybrid open system,dissipated by external bosonic thermal reservoirs.By applying coherent phonon states embedded in the dressed quantum master equation,we are capable of dealing with arbitrary qubit-phonon coupling strength.It is counterintuitively found that the effect of negative differential thermal conductance is absent at strong qubit-phonon hybridization,but becomes profound at weak qubit-phonon coupling regime.The underlying mechanism of decreasing heat flux by increasing the temperature bias relies on the unidirectional transitions from the up-spin displaced coherent phonon states to the down-spin counterparts,which seriously freezes the qubit and prevents the system from completing a thermodynamic cycle.Finally,the effects of perfect thermal rectification and giant heat amplification are unraveled,thanks to the effect of negative differential thermal conductance.These results of the nonequilibrium qubit-phonon open system would have potential implications in smart energy control and functional design of phononic hybrid quantum devices.

关键词： phonon quantum coherent

EPIC STAR:a reliable and efficient approach for phonon- and impurity-limited charge transport calculations

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2020年第1期6卷 1261-1271页

作者： Tianqi Deng Gang Wu Michael B.Sullivan Zicong Marvin Wong Kedar Hippalgaonkar Jian-Sheng Wang Shuo-Wang Yang Institute of High Performance Computing Agency for ScienceTechnology and Research1 Fusionopolis Way#16-16 ConnexisSingapore 138632Singapore School of Materials Science and Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore Institute of Materials Research and Engineering Agency for ScienceTechnology and Research2 Fusionopolis Way#08-03 InnovisSingapore 138634Singapore Department of Physics Faculty of ScienceNational University of Singapore2 Science Drive 3Singapore 117551Singapore

A computationally efficient first-principles approach to predict intrinsic semiconductor charge transport properties is proposed.By using a generalized Eliashberg function for short-range electron–phonon scattering and analytical expressions for long-range electron–phonon and electron–impurity scattering,fast and reliable prediction of carrier mobility and electronic thermoelectric properties is realized without empirical parameters.This method,which is christened“Energy-dependent phonon-and Impuritylimited Carrier Scattering Time AppRoximation(EPIC STAR)”approach,is validated by comparing with experimental measurements and other theoretical approaches for several representative semiconductors,from which quantitative agreement for both polar and non-polar,isotropic and anisotropic materials is achieved.The efficiency and robustness of this approach facilitate automated and unsupervised predictions,allowing high-throughput screening and materials discovery of semiconductor materials for conducting,thermoelectric,and other electronic applications.

关键词： phonon charge reliable