Low energy phonon spectrum and its parameterization in pure KTaO 3 below 80
نویسندگان
چکیده
High resolution data on low energy phonon branches (acoustic and soft optic) along the three principal symmetry axes in pure KTaO3 were obtained by cold neutron inelastic scattering between 10 and 80 K. Additional off-principal axis measurements were performed to characterize the dispersion anisotropy (away from the <100> and <110> axes). The parameters of the phenomenological model proposed by Vaks [28] are refined in order to successfully describe the experimental low temperature (10 < T < 100 K) dispersion curves, over an appreciable reciprocal space volume around the zone center (|q| < 0.25 rlu). The refined model, which involves only 4 temperature-independent adjustable parameters, is intended to serve as a basis for quantitative computations of multiphonon processes.
منابع مشابه
نرم شدگی فونونهای انرژی بالا با گذار عایق - ابررسانا در سیستم ابررسانای Ba1-xKxBiO3
Single crystals of Ba1-xKxBiO3 compound for 0 < x <0.6 from insulator to superconducting region have been grown by electrochemical method. The crystals have been characterized by powder x-ray diffraction and Laue x-ray to determine the crystal structure, formed phases and potassium concentration. Inelastic x-ray scattering spectrum of the crystals has been studied to investigate the phonon pro...
متن کاملPhonons in Nanocrystalline 57Fe
We measured the phonon density of states (DOS) of nanocrystalline Fe by resonant inelastic nuclear g-ray scattering. The nanophase material shows large distortions in its phonon DOS. We attribute the high energy distortion to lifetime broadening. A damped harmonic oscillator model for the phonons provides a low quality factor, Qu, averaging about 5, but the longitudinal modes may have been broa...
متن کاملPhonon-assisted resonant tunneling through a triple-quantum- dot: a phonon-signal detector
– We study the effect of electron-phonon interaction on current and zero-frequency shot noise in resonant tunneling through a series triple-quantum-dot coupling to a local phonon mode by means of a nonperturbative mapping technique along with the Green function formulation. By fixing the energy difference between the first two quantum dots to be equal to phonon frequency and sweeping the level ...
متن کاملMode-coupling in a relativistic two-phonon model
The relativistic quasiparticle time blocking approximation (RQTBA), developed recently as a consistent combination of the covariant energy density functional theory (CEDFT) and the modern extensions of the Landau– Migdal theory of finite fermi systems, is reviewed in Ref. [1]. In the RQTBA, starting from the covariant energy functional, phonon energies and their vertices are calculated without ...
متن کاملElectronic Properties of α ′ - NaV 2 O 5
1 General properties of α −NaV 2 O 5 and motivation for a spectroscopic study Introduction – α −NaV 2 O 5 is one of the several phases in the class of Na x V 2 O 5 systems [1] and until now it is by far the most studied of them. Since 1996 this compound (denoted in the following simply by NaV 2 O 5) has received considerable attention because it was thought to be the second realization, after C...
متن کامل