Related papers: Low bending rigidity and large Young's modulus dri…
We develop the theory for dynamics of the out-of-plane deformations in flexible two-dimensional materials. We focus on study of attenuation of flexural phonons in free-standing crystalline membranes. We demonstrate that the dynamical…
Anharmonic effects in an atomic monolayer thin crystal with honeycomb lattice structure are investigated by analytical and numerical lattice dynamical methods. Starting from a semi-empirical model for anharmonic couplings of third and…
Despite many of the applications of graphene rely on its uneven stiffness and high thermal conductivity, the mechanical properties of graphene, and in general of all 2D materials, are still elusive. The harmonic theory predicts a quadratic…
Classical thermal transport theories that preserve rotational symmetry, predict strong anharmonic scattering of out-of-plane lattice vibrational modes called flexural phonons in flat suspended graphene sheets. Such strong scattering…
We investigate the elastic behavior of two-dimensional crystalline membrane embedded into real space taking into account the presence an arbitrary number of flexural phonon modes $d_c$ (the number of out-of-plane deformation field…
The electronic bandgap of a material is often fixed after fabrication. The capability to realize on-demand and non-volatile control over the bandgap will unlock exciting opportunities for adaptive devices with enhanced functionalities and…
Full ranges of both hybrid plasmon-mode dispersions and their damping are studied systematically by our recently developed mean-field theory in open systems involving a conducting substrate and a two-dimensional (2D) material with a buckled…
Heat transport by acoustic phonons in 2D materials is fundamentally different from that in 3D crystals because the out-of-plane phonons propagate in a unique way that strongly depends on tension and bending rigidity. Since in-plane and…
We study the effect exerted by the electrons on the flexural phonons in graphene, accounting for the attractive interaction created by the exchange of electron-hole excitations. Combining the self-consistent computation of the phonon…
Hexagonal two-dimensional materials with broken inversion symmetry (as BN or transition metal dichalcodenides) are known to sustain chiral phonons with finite angular momentum, adding a further useful degree of freedom to the extraordinary…
The resonance frequency of ultra-thin layered two-dimensional (2D) materials changes nonlinearly with the tension induced by the pressure from the surrounding gas. Although the dynamics of pressurized 2D material membranes have been…
Anomalous thermal expansion behaviour of several open frame-work compounds has been extensively investigated using the techniques of inelastic neutron scattering and lattice dynamics. These compounds involve increasing level of structural…
We develop the microscopic theory for the attenuation of out-of-plane phonons in stressed flexible two-dimensional crystalline materials. We demonstrate that the presence of nonzero tension strongly reduces the relative magnitude of the…
The long-wavelength behavior of vibrational modes plays a central role in carrier transport, phonon-assisted optical properties, superconductivity, and thermomechanical and thermoelectric properties of materials. Here, we present general…
We observe anharmonic decay of the photoexcited coherent A1g phonon in bismuth to points in the Brillouin zone where conservation of momentum and energy are satisfied for three-phonon scattering. The decay of a coherent phonon can be…
We develop a unified theory for the second sound in two dimensional materials. Previously studied drifting and driftless second sound are two limiting cases of the theory, corresponding to the drift and diffusive part of the energy flux,…
In two-dimensional crystals that lack symmetry under reflections on the horizontal plane of the lattice (non-$\sigma_{\rm h}$-symmetric), electrons can couple to flexural modes (ZA phonons) at first order. We show that in materials of this…
Digital video-microscopy measurements are reported of both elastic bandstructures and overdamped phonon decay times in two-dimensional colloidal crystals. Both quantities together allow to determine the friction coefficients along various…
Extreme confinement of electromagnetic energy by phonon polaritons holds the promise of strong and new forms of control over the dynamics of matter. To bring such control to the atomic-scale limit, it is important to consider phonon…
Crystalline materials with ultralow thermal conductivity are highly desirable for thermoelectric applications. Many known crystalline materials with low thermal conductivity, including PbTe and Bi2Te3, possess a special kind of chemical…