相关论文: Exposing the hidden influence of selection rules o…
In this work we present the results of an inelastic x-ray scattering experiment detailing the behavior of the transverse acoustic [110] phonon in BaFe2As2 as a function of temperature. When cooling through the structural transition…
Various two-dimensional (2D) materials with graphene-like buckled structure emerge, and the $\beta$-phase AsP monolayer has been recently proposed to be thermodynamically stable from first-principles calculations. The studies of thermal…
Anharmonic lattice vibrations govern the thermal dynamics in materials and present how the atoms interact and how they conduct heat. An indepth understanding of the microscopic mechanism of phonon anharmonicity in condensed systems is…
The detailed temperature dependence of the infrared-active mode in Fe$_{1.03}$Te ($T_N\simeq 68$ K) and Fe$_{1.13}$Te ($T_N\simeq 56$ K) has been examined, and the position, width, strength, and asymmetry parameter determined using an…
Probing phonons, quasi-particle excitations and their coupling has enriched our understanding of these 2D materials and proved to be crucial for developing their potential applications. Here, we report comprehensive temperature, 4-330 K,…
Plasmonic excitations behave fundamentally different in layered materials in comparison to bulk systems. They form gapless modes, which in turn couple at low energies to the electrons. Thereby they can strongly influence superconducting…
Ammonium sulfate is a giant inverse barocaloric material that is cheaply and commercially available. Exploiting its potential for cooling applications requires an understanding of the mechanism driving the entropy change. Here we report an…
Effects of strong phonon anharmonicity of a type-I clathrate Ba$_{\rm 8}$Ga$_{\rm 16}$Sn$_{\rm 30}$ induced by quadruple-well potential of guest atoms were investigated. Phonon transport including coherent interbranch component was analyzed…
We formulate a first-principle scheme for structural optimization at finite temperature ($T$) based on the self-consistent phonon (SCP) theory, which accurately takes into account the effect of strong phonon anharmonicity. The…
The Seebeck coefficient and electrical conductivity are two critical quantities to optimize simultaneously in designing thermoelectric materials, and they are determined by the dynamics of carrier scattering. We uncover a new regime where…
Interest in high entropy alloy thermoelectric materials is predicated on achieving ultralow lattice thermal conductivity $\kappa\sub{L}$ through large compositional disorder. However, here we show that for a given mechanism, such as mass…
Suppressed three-phonon scattering processes have been considered to be the direct cause of materials exhibiting significant higher-order four-phonon interactions. However, after calculating the phonon-phonon interactions of 128…
The finite size effects of the thermal conductivity $\kappa$ have been studied in the phonon space. It is found that only a few phonon modes are selected to take part in the thermal transport when the size $L$ of the system is decreased.…
We have studied the effects of phonon-boundary scattering on the thermal transport in topological Kondo insulator, SmB$_6$. The studies have been performed by using the $3\omega$ method in the temperature range 300K - 3K. We show that the…
The thermal Hall effect, which arises when heat flows transverse to an applied thermal gradient, has become an important observable in the study of quantum materials. Recent experiments found a large thermal Hall conductivity $\kappa_{xy}$…
The scattering of electrons with polar optical phonons (POP) is an important mechanism that limits electronic transport and determines electron mobility in polar materials. This is typically a stronger mechanism compared to non-polar…
The material dependence of phonon-polariton based in-plane thermal conductance is investigated by examining systems composed of air and several wurtzite and zinc-blende crystals. Phonon-polariton based thermal conductance varies by over an…
The standard theoretical understanding of the lattice thermal conductivity, $\kappa_{\ell}$, of semiconductor alloys assumes that mass disorder is the most important source of phonon scattering. In contrast, we show that the hitherto…
The Raman selection rules arise from the crystal symmetry and then determine the Raman activity and polarization of scattered phonon modes. However, these selection rules can be broken in resonant process due to the strong electron-phonon…
Prevailing nanostructuring strategies focus on increasing phonon scattering and reducing the mean-free-path of phonons across the spectrum. In nanoporous Si materials, for example, boundary scattering reduces thermal conductivity…