Suppression of anomalous phonon scattering via Zn substitution in the metallic phase of Cu1-xZnxIr2S4

2022 ◽  
pp. 413675
Author(s):  
Kenta Hashimoto ◽  
Suguru Kitani ◽  
Hitoshi Kawaji
Keyword(s):  
Phonon Scattering ◽  
Metallic Phase ◽  
Zn Substitution

THERMAL TRANSPORT OF MgB2 SUPERCONDUCTORS: INTERPLAY BETWEEN ELECTRON AND LATTICE-IMPURITY SCATTERING

2007 ◽  
Vol 21 (26) ◽  
pp. 4517-4536 ◽  
Author(s):  
DINESH VARSHNEY ◽  
M. NAGAR ◽  
K. K. CHOUDHARY
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Impurity Scattering ◽  
Metallic Phase ◽  
Scattering Mechanism ◽  
S Wave ◽  
Lattice Contribution ◽  
Relaxation Time Approximation

We use the Kubo model to calculate the lattice contribution to the thermal conductivity (κph) in MgB 2 superconductors. The theory is formulated when heat transfer is limited by the scattering of phonons from defects, grain boundaries, charge carriers, and phonons. The lattice thermal conductivity in normal state of MgB 2 superconductors dominates and is an artifact of strong phonon-impurity and -phonon scattering mechanism. Later on, the electronic contribution to the thermal conductivity (κe) is calculated within relaxation time approximation for π and σ band carriers with s wave symmetry. Such an estimate sets an upper bound on κe and is about 30% of the total heat transfer at room temperature. The validity of the Wiedemann Franz law is also examined and an enhanced Lorenz number is obtained. Both these channels for heat transfer are clubbed and κ tot develops a broad peak at about 120 K, before falling off at higher temperatures weakly. The anomalies reported are well-accounted in terms of the scattering mechanism by phonon and electron with impurities. It is shown that the behavior of the thermal conductivity is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between electron and lattice contributions. The contribution of carriers toward κ is substantial and is due to the fact that the carriers are condensed and do not carry entropy. We include comparisons with other theoretical calculations on κe and available experimental data. The numerical analysis of heat transfer in the metallic phase of MgB 2 shows similar results as those revealed from experiments.

Thermal conductivity in the ferromagnetic metallic phase of monovalent Ag doped manganites

2014 ◽  
Vol 03 (03) ◽  
pp. 1450015
Author(s):  
Dinesh Varshney ◽  
E. Khan ◽  
Dinesh Choudhary
Keyword(s):  
Thermal Conductivity ◽  
Relaxation Rate ◽  
Acoustic Phonon ◽  
Phonon Scattering ◽  
Metallic Phase ◽  
Charge Carriers ◽  
Metallic State ◽  
Scattering Mechanism ◽  
Doped Manganites ◽  
Heat Carriers

The thermal conductivity (κ) behavior in La 0.75 Ag 0.25 MnO 3 manganites is investigated by probing the phonon, carrier and magnon scattering sources. The acoustic phonon contribution to the thermal conductivity (κph) is investigated within the Debye-type relaxation rate approximation. The scattering of phonon from defects, grain boundaries, charge carriers, and phonon are the major sources. La 0.75 Ag 0.25 MnO 3 witnesses the dominant κph and is artifact of strong phonon–impurity and phonon–phonon scattering mechanism in the ferromagnetic metallic state. The carrier contribution to the thermal conductivity (κe) is estimated following the Wiedemann–Franz law. In the metallic phase spin waves (κm) also shows the importance. It is noticed that κm increases with a T2 dependence on the temperature. The behavior of thermal conductivity (κ) in La 0.75 Ag 0.25 MnO 3 is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between electron, magnon, and phonon contributions.

Towards quantitative simulations of inelastic electron diffraction patterns and images

1992 ◽  
Vol 50 (2) ◽  
pp. 1170-1171
Author(s):  
Z. L. Wang
Keyword(s):  
Phonon Scattering ◽  
Incident Beam ◽  
Dynamical Theory ◽  
Inelastic Electron ◽  
Additional Advantage ◽  
Coupled Equations ◽  
Atomic Vibrations ◽  
Diffraction Patterns ◽  
Primary Advantage ◽  
The One

A new dynamical theory has been developed based on Yoshioka's coupled equations for describing inelastic electron scattering in thin crystals. Compared to existing theories, the primary advantage of this theory is that the incoherent summation of the diffracted intensities contributed by electrons after exciting vast numbers of different excited states has been evaluated before any numerical calculation. An additional advantage is that the phase correlations of atomic vibrations are considered, so that full lattice dynamics can be combined in the phonon scattering calculation. The new theory has been proven to be equivalent to the inelastic multislice theory, and has been applied to calculate energy-filtered diffraction patterns and images formed by phonon, single electron and valence scattered electrons.A calculated diffraction pattern of elastic and phonon scattered electrons for a parallel incident beam case is in agreement with the one observed (Fig. 1), showing thermal diffuse scattering (TDS) streaks and Kikuchi pattern.

Dynamic studies of silicide-mediated crystallization of amorphous silicon

1992 ◽  
Vol 50 (2) ◽  
pp. 1352-1353
Author(s):  
C. Hayzelden ◽  
J. L. Batstone
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Metallic Phase ◽  
Single Crystal Substrate ◽  
Free Electrons ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
High Resolution Tem

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

Metallic phase stabilization and phase diagram of (ET)3(HSO4)2

1991 ◽  
Vol 1 (10) ◽  
pp. 1365-1370 ◽  
Author(s):  
N. D. Kush ◽  
V. N. Laukhin ◽  
A. I. Schegolev ◽  
E. B. Yagubskii ◽  
E. Yu. Alikberova ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Metallic Phase ◽  
Phase Stabilization

DEGREE OF VALENCE MIXING IN THE METALLIC PHASE OF SmS AND IN TmSe

1976 ◽  
Vol 37 (C4) ◽  
pp. C4-267-C4-270 ◽  
Author(s):  
B. BATLOGG ◽  
A. SCHLEGEL ◽  
P. WACHTER
Keyword(s):  
Metallic Phase ◽  
Valence Mixing

TEMPERATURE DEPENDENCE BEHAVIOR OF ELECTRICAL RESISTIVITY IN NOBLE METALS AT LOW TEMPERATURES

2014 ◽  
Vol 5 (3) ◽  
pp. 982-992 ◽  
Author(s):  
M AL-Jalali
Keyword(s):  
Experimental Data ◽  
Electrical Resistivity ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Low Temperatures ◽  
Noble Metals ◽  
Phonon Scattering ◽  
Theoretical Models ◽  
Residual Resistivity ◽  
Electron Phonon Scattering

Resistivity temperature – dependence and residual resistivity concentration-dependence in pure noble metals(Cu, Ag, Au) have been studied at low temperatures. Dominations of electron – dislocation and impurity, electron-electron, and electron-phonon scattering were analyzed, contribution of these mechanisms to resistivity were discussed, taking into consideration existing theoretical models and available experimental data, where some new results and ideas were investigated.

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