Overview
Thermal management
Thermoelectrics
Thermal insulation
Thermal protection
Thermal energy storage
Batteries
Machine Learning
Theoretical methods:
Density functional theory (DFT) packages: (phase stability, phase transition/ transformation, mechanical/ electrical/ thermodynamical/ thermal/ thermoelectical properties, atomic vibration, ion migration, ab-initio molecular dynamics (AIMD)) -- VASP, Abinit, ELK, Quantum Espresso
Classical molecular dynamics (MD) simulations, e.g., LAMMPS
Tight-binding molecular dynamics (TBMD) -- DFTB
Harmonic lattice dynamics (LD) calculations, e.g., (my own code, GULP, Phonopy)
Phonon normal mode analysis (NMA), i.e., spectral energy density (SED) analysis (my own code & my tool)
First principles calculations of three- and four-phonon scattering rates (my own developed method & code, Thirdorder, ShengBTE)
Spectral phonon temperature (SPT) method (my own developed method & code)
Exact solution to linearized Boltzmann transport equation (BTE) including three- and four-phonon scattering (my own developed method & code)
Finite difference and finite volume methods (FDM, FVM) in heat, mass, and momentum transfer (my own code)
Gray BTE -- FVM solver
Experimental methods:
3-Omega Thermal Conductivity Measurement
Laser Flash Thermal Conductivity measurement
Electron microscopy
Ultra-high thermal conductivity materials
Diamond, BAs, SiC, etc.
Semiconductors
C, Si, Ge, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, CdTe, etc.
impurity, defects, alloy, nanostructures (nanowires, nanomeshes, superlattices, etc.)
Ultra-high temperature materials
HfB2, ZrB2, HfC, ZrC, HfN, ZrN, etc.
Thermoelectric materials & nanostructures
SnSe, GeTe, SnS, PbS, PbTe, Bi2Te3, Sb2Te3, Bi2Se3, Bi2S3, etc.
PbTe-Bi2Te3, PbTe-Bi2-xSbxTe3, Bi2Te3-xSex, Bi13S18I2 heterostructures & nanocomposites
Cage-structure materials: skutterudites, clathrates
Emerging 1D/2D layered materials
III, IV, V groups: Graphene, boron nitride, carbon nanotube (CNT), black phosphorus, phosphorene, silicene, germanene, borophene, etc.
Transition-metal chalcogenide (MoS2, MoSe2, VS2, VSe2, WS2, WSe2, PdSe2, ZrTe5, etc.)
Their nanostructures: graphene nanomesh & nanoribbon, graphene/substrate & sandwich, graphene/BN superlattice & heterostructure, etc.
Complex oxides, thin films, surfaces, heterostructures
Thermal, electrical: LaCoO3, LaxSr1-xCoO3-d, etc. Magnetic, electrical: SrTiO3, LaxSr1-xMnO3, etc.
Rutile: RuO2, CrO2, PdO2, ReO2, RhO2, OSO2, IrO2, etc.
Lithium ion related
Batteries: LiCoO2, LiFePO4, Li10GeP2S12, LiNiO2, MgV2O5, CaV2O5, etc.
LiNbO2 Memristors
Molecules, amorphous, organic materials
polymers (polyethylene, polystyrene, polypropylene, EVOH, etc.), SiO2
Highlight: Four-Phonon Processes
Phonon is the microscopic heat carrier in solids, and the phonon-phonon scattering is the main thermal resistance mechanism that determines the thermal transport in solids.
Four-phonon scattering is a multi-phonon process, and its evaluation has been a long-standing challenge for decades.
We solved this problem and found the four-phonon scattering to be of great importance in:
Low-thermal-conductivity anharmonic materials, such as all ionic crystals, thermoelectric materials, salts, complex oxides, etc.
Simple crystals with acoustic-optical phonon band gaps
Most materials at high temperatures
Optical phonons of most materials
Materials with reflection symmetry (such as single-layer grahpene, BN, CNT)
References:
T. Feng, X. Ruan*, "Quantum mechanical prediction of four-phonon scattering rates and reduced thermal conductivity of solids", Physical Review B 93, 045202 (2016). [Link] [PDF]
T. Feng, L. Lindsay, X. Ruan*, "Four-phonon scattering significantly reduces intrinsic thermal conductivity of solids", Physical Review B: Rapid Communications 96 (16), 161201 (2017). [Link] [PDF+SI] (This work is highlighted by several academic news: see our News) (This work is intensively cited by three Science reports: see our News)
T. Feng, Xiulin Ruan*, "Four-phonon scattering reduces intrinsic thermal conductivity of graphene and the contributions from flexural phonons", Physical Review B 97, 045202 (2018). [Link] [PDF]
T. Feng*, X. Yang, X. Ruan*, "Phonon anharmonic frequency shift induced by four-phonon scattering calculated from first principles", Journal of Applied Physics 124, 145101 (2018). [Link] [PDF]
X. Yang, T. Feng, J. Li, X. Ruan, "Stronger role of four-phonon scattering than three-phonon scattering in thermal conductivity of III-V semiconductors at room temperature", Physical Review B 100, 245203, (2019). [Link]
X. Yang#, T. Feng#, J. S. Kang, Y. Hu, J. Li, X. Ruan*, Observation of strong higher-order lattice anharmonicity in Raman and infrared response, Physical Review B 101, 161202(R) (2020). [Link] (# these authors contributed equally)
Z. Tong, X. Yang, T. Feng, H. Bao, X. Ruan, First-principles predictions of temperature-dependent infrared dielectric function of polar materials by including four-phonon scattering and phonon frequency shift, Phys. Rev. B 101, 125416 (2020). [Link]
(Book Chapter) T. Feng*, X. Ruan*, Higher-order phonon scattering: advancing the quantum theory of phonon linewidth, thermal conductivity and thermal radiative properties. in Nanoscale Energy Transport 2-1-2–44 (IOP Publishing, 2020). https://doi.org/10.1088/978-0-7503-1738-2ch2 (invited book) [Link]
T. Feng*, A. O'Hara, S. T. Pantelides*, "Quantum Prediction of Ultra-Low Thermal Conductivity in Lithium Intercalation Materials", Nano Energy, 104916 , 2020. https://doi.org/10.1016/j.nanoen.2020.104916 [PDF] [SI]