Related papers: A New Approach to Phonon Anharmonicity
We investigate the ultrafast optical response of PbTe to an intense single-cycle terahertz pulse, resonant with the soft transverse optical (TO) phonon mode of the crystal. We detect multifrequency oscillations of the reflectance…
A method to evaluate the particle-phonon coupling (PC) corrections to the single-particle energies in semi-magic nuclei, based on a direct solving the Dyson equation with PC corrected mass operator, is used for finding the odd-even mass…
Band structures encode electronic, optical, and acoustic properties of matter and can serve as an essential tool in material discovery and design. Dispersion anomalies -- sharp, non-standard features in the frequency-wavenumber relation --…
Phonon, the collective excitation of lattice vibration in the crystal, has been put forward as a means to search for light dark matter. However, the accurate modeling of the multi-phonon production process is challenging in theory. The…
The effects of phonon anharmonicity, phonon-magnon and electron-phonon interactions on the temperature dependence of Raman optical phonon modes are theoretically investigated. Besides of the Klemens result for the phonon width due to…
We present an \textit{ab initio} framework to calculate anharmonic phonon frequency and phonon lifetime that is applicable to severely anharmonic systems. We employ self-consistent phonon (SCPH) theory with microscopic anharmonic force…
Terahertz and far-infrared electric and magnetic responses of hexagonal piezomagnetic YMnO3 single crystals are investigated. Antiferromagnetic resonance is observed in the spectra of magnetic permeability mu_a [H(omega) oriented within the…
The refraction properties of phononic crystals are revealed by examining the anti-plane shear waves in doubly periodic elastic composites with unit cells containing rectangular and/or elliptical inclusions. The band-structure, group…
Amongst the X(Sn,Pb)Y$_3$ perovskites currently under scrutiny for their photovoltaic applications, the cubic B-$\alpha$ phase of CsSnI$_3$ is arguably the best characterized experimentally. Yet, according to the standard harmonic theory of…
Phonon properties of realistic materials are routinely calculated within the Density Functional Perturbation Theory\,(DFPT). This is a semi--classical approach where the atoms are assumed to oscillate along classical trajectories immersed…
The molecular-crystal model, that describes a one-dimensional electron gas interacting with quartic anharmonic lattice vibrations, offers great potentials in the mapping of a relatively wide range of low-dimensional fermion systems coupled…
We develop a formalism for the calculation of the frequency band structure of a phononic crystal consisting of non-overlapping elastic spheres, characterized by Lam\'e coefficients which may be complex and frequency dependent, arranged…
Including the effect of lattice anharmonicity on electron-phonon interactions has recently garnered attention due to its role as a necessary and significant component in explaining various phenomena, including superconductivity, optical…
Phonon quasi-particles have been monumental in microscopically understanding thermodynamics and transport properties in condensed matter for decades. Phonons have one-to-one correspondence with harmonic eigenstates and their energies are…
We report first-principles calculations of the phonon dispersion spectrum, thermal expansion, and heat capacity of uranium dioxide. The so-called direct method, based on the quasiharmonic approximation, is used to calculate the phonon…
We measured phonon dispersion in single crystal EuTiO$_3$ using inelastic x-ray scattering. A structural transition to an antiferrodistortive phase was found at a critical temperature $T_0$=287$\pm$1 K using powder and single-crystal x-ray…
Dispersion equations are a common paradigm of collective excitation physics. However, in some systems, dispersion equations contain multivalued functions and their solutions are ambiguous. As an example, we consider graphene on a polar…
The paper examines superradiance in impurity crystals in the field of a coherent phonon wave excited by two ultrashort laser pulses via Raman scattering processes at the moment of preparation of the initial state of an ensemble of emitters.…
Detailed understanding of vibrational heat transfer mechanisms between solids is essential for the efficient thermal engineering and control of nanomaterials. We investigate the frequency dependence of anharmonic scattering and interfacial…
A nonperturbative theory of multiphonon anharmonic transitions between energy levels of a local mode is presented. It is shown that the rate of transitions rearranges near the critical level number $n_{cr}$: at smaller $n$ the process slows…