相关论文: Phonon pseudoangular momentum in $\alpha$-MoO$_3$

Angular momentum (AM), a fundamental concept describing the rotation of an object about an axis, profoundly influences all branches of physics. In condensed matter, AM is intimately related to the emergence of topological quantum states,…

The current understanding of chirality suggests the existence of a connection between structure and angular momentum, including spin. This is particularly emphasised in the chiral induced spin selectivity effect, where chiral structures act…

The influence of the specific geometry of three-dimensional confinement on electron- vibrational coupling in InAs/GaAs nanoclusters shaped as highly oblate ellipsoids of revolution is considered. Optical phonon relaxation processes are…

Hyperbolic crystals like {\alpha}-MoO$_3$ can support large wavevectors and photon density as compared to the commonly used dielectric crystals, which makes them a highly desirable platform for compact photonic devices. The extreme…

Exact eigen modes with orbital angular momentum (OAM) in the complex media of unmagnetized homogeneous plasma are studied. Three exact eigen modes with OAM are discovered, i.e., photons, phonons, and plasmons. It is found that an OAM photon…

Quasiparticles describe collective excitations in many-body systems, and their symmetry classification is of fundamental importance because they govern physical processes on various timescales, e.g., excited states, transport phenomena, and…

We have carried out temperature-dependent x-ray diffraction and Raman scattering experiments on powder $Cs_3Bi_2Br_9$. Trigonal to monoclinic structural transition at around 95 K is discussed and shown to be driven by the softening of the…

A positive muon is a spin-1/2 particle. Beams of muons with all their spins polarized can be prepared and subsequently implanted in various types of condensed matter. The subsequent precession and relaxation of their spins can then be used…

Recently, it has been predicted that the Berry curvature of electrons can produce an angular momentum for phonons. In systems with time-reversal symmetry, the direction of the phonon angular momentum is locked to the phonon wave vector.…

We experimentally observe the generation of magnon harmonics and subharmonics in an on-chip surface acoustic wave resonator incorporating a thin Co$_{20}$Fe$_{60}$B$_{20}$ film, using micro-focused Brillouin light scattering. In our…

We demonstrate through first-principles calculations applied to the K$_{3}$NiO$_{2}$ crystal that a structural phase transition from an achiral to a chiral phase can be mediated by a degenerate soft phonon mode and controlled by pressure…

We develop a kinetic theory for twisted density waves (phonons), carrying a finite amount of orbital angular momentum, in large magneto optical traps, where the collective processes due to the exchange of scattered photons are considered.…

Density functional perturbation theory calculations of alpha-quartz using extended norm conserving pseudopotentials have been used to study the elastic properties and phonon dispersion relations along various high symmetry directions as a…

We theoretically studied the phonon properties of the triangular-, stripe- and honeycomb-type electronic crystals recently found in two-dimensional semiconductor moir\'e patterns. By analyzing the phonon dispersions, we found the…

Conventional wisdom suggests that one photon that carries one unit of angular momentum can change the spin angular momentum of a magnetic system with one unit (delta Ms = +-1) at most. This would imply that a two-photon scattering process…

Lattice vibrations carrying angular momentum, known as chiral phonons, have emerged as a promising route to control and understand complex material properties, yet their deterministic manipulation remains largely unexplored. Here we…

We use a combination of polarized Raman spectroscopy experiment and model magnetism-phonon coupling calculations to study the rich magneto-Raman effect in the two-dimensional (2D) magnet $\mathrm{CrI_3}$. We reveal a novel…

Despite the growing interest in phonon angular momentum (AM) in recent years, current studies remain limited to a few materials due to the constraints imposed by time reversal symmetry on macroscopic phonon AM. In this work, we…

I provide a pedagogical introduction to the notion of pseudomomentum for waves in a medium, and show how changes in pseudomomentum may sometimes be used to compute real forces. I then explain how these ideas apply to sound waves in a fluid.…

We investigate the spin-orbit coupling effect in a two-dimensional Wigner crystal. We show that sufficiently strong spin-orbit coupling and an appropriate sign of g-factor could transform the Wigner crystal to a topological phonon system.…