Phonon Spectra of Chain TlSe and TlInSe₂: Density Functional Theory Based Study

Abstract

Quantum turbulence, easily generated in superfluid helium, consists of a disordered tangle of thin, discrete vortex lines of quantised circulation which move in a fluid without viscosity. In this report we show that, in very intense quantum turbulence, the vortex tangle contains small coherent vortical structures (bundles of quantised vortices) which arise from the fundamental Biot-Savart interaction between vortices, and which are similar to the intermittent, coherent structures ("worms") observed in ordinary viscous turbulence. Our result highlights the similarity between quantum turbulence and ordinary turbulence, and sheds new light into the origin of the "worms" in ordinary turbulence.

Debye temperatures and Grueneisen parameters of chain TlSe and TlInSe2

“…where n is the number of atoms per molecular unit, k B -the Boltzman constant, T -temperature, g(ω) -the normalized DOS, ω m -the highest limit of the phonon frequency , and N -a normalization factor. The required DOS values were obtained by sampling the dynamical matrices in 32×32×32 wave vectors of the BZ [15]. The bulk modulus values have been obtained by relaxing the internal positional parameters, minimizing Hellman-Feynman forces, and fitting both Murnaghan [20] and Birch-Murnaghan [21] equations of state to the obtained total energy dependence upon unit cell volume.…”

“…More detailed analysis of γ G of TlSe and TlInSe 2 will be given after direct calculations of the elastic constants and anisotropic linear expansion coefficients within the framework of the obtained phonon band structure [15]. These calculations are under way.…”

Temperature-dependent and pump-probe ellipsometric studies of TlInSe2

“…The later was performed in an attempt to study other than the local heating effect on optical constants of TlInSe 2 . The local heating was expected to be large in this 1D-material for the low thermal conductivity caused by Einstein-like transversal acoustic modes and strong inter-mode interaction [14].…”

TlSe İnce Filminin Dalgalı İletkenliği

“…Talyum Selenür (Thalium Selenide -TlSe) cisim merkezli tetragonal yapıya ( body centered-tetragonalbct) sahip III-VI grubu bir bileşik olup, yapısı iyonikkovalent bağlı atomları içeren zincirlerle tarif edilir [1][2][3]. TlSe kristalinin yasak band aralığı oda sıcaklığında 0,69-1,10 eV olarak belirlenmiştir [2,3]. Ayrıca oda sıcaklığında Hall hareketliliği [110] ve [001] yönlerinde μ ′ = 42,66 m 2 V −1 s −1 ve μ ′′ = 112,2 cm 2 V −1 s −1 dir [4][5][6].…”