Ultrasonic Attenuation and the Fermi Surface of Arsenic

1965 ◽  
Vol 140 (4A) ◽  
pp. A1355-A1364 ◽  
Author(s):  
J. B. Ketterson ◽  
Y. Eckstein
Keyword(s):  
Fermi Surface ◽  
Ultrasonic Attenuation

Strain dependence of the Fermi surface and ultrasonic attenuation in tin

1969 ◽  
Vol 30 (4) ◽  
pp. 235-236 ◽  
Author(s):  
J.M. Perz ◽  
R.H. Hum ◽  
P.T. Coleridge
Keyword(s):  
Fermi Surface ◽  
Ultrasonic Attenuation ◽  
Strain Dependence

Finite frequency ultrasonic attenuation in an anisotropic superconductor

1978 ◽  
Vol 56 (10) ◽  
pp. 1395-1398
Author(s):  
K. M. Hong ◽  
J. P. Carbotte
Keyword(s):  
Fermi Surface ◽  
Energy Gap ◽  
Ultrasonic Attenuation ◽  
Pair Breaking ◽  
Finite Frequency ◽  
Finite Amount ◽  
Anisotropic Superconductor ◽  
Gap Values

The ultrasonic attenuation of an isotropic superconductor shows a finite jump at a frequency of twice the energy gap because of the onset of pair breaking. For an anisotropic superconductor it is shown that the rise in attenuation proceeds in steps when there exist regions on the Fermi surface with distinct gap values separated by a finite amount.

Theory of ultrasonic attenuation in metals and magneto-acoustic oscillations

1960 ◽  
Vol 257 (1289) ◽  
pp. 165-193 ◽  
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Free Path ◽  
Electric Fields ◽  
Free Electron ◽  
Noble Metals ◽  
Deformation Parameter ◽  
Ultrasonic Attenuation ◽  
Acoustic Oscillations ◽  
Oscillatory Behaviour

The attenuation of an ultrasonic wave by direct interaction with the conduction electrons in a metal is analyzed without making any special assumptions about the shape of the Fermi surface. The problem is reduced to a calculation of the currents set up in a stationary lattice by forces on the electrons, some real (due to electric fields) and some fictitious to describe the disturbances due to the passage of the wave. The fictitious forces have their origin in the relative motion of different parts of the metal and in the change in shape of the equilibrium form of the Fermi surface as a result of lattice deformation. It is assumed, as is valid for ultrasonic frequencies below about 10 9 c/s, that the electric fields serve to annul any electronic current relative to the lattice. The expressions obtained are qualitatively similar to the earlier results for a free-electron model, in particular the attenuation tends to a con­stant limit as the electronic free path becomes infinite. Only for a pure longitudinal wave is the limit simple in form and there it is determined by the Gaussian curvature and the mean square value of the deformation parameter round that zone of the Fermi surface on which the electrons move parallel to the wave front. The analysis is extended to cover the situation which arises in a transverse magnetic field, in the limit when the free path is long compared with the electronic orbit perimeters. The results are very complicated, but qualitatively similar to the free-electron results in the types of oscillatory behaviour predicted and in the limiting values of the attenuation as the magnetic field increases without limit; if there are open orbits present, however, the limiting behaviour is changed, the attenuation of longitudinal waves for instance tending to infinity as H 2 . Although the oscillatory behaviour may usually be governed by the extreme exten­sions of the Fermi surface in a direction normal to H and to the direction of propagation, it is suggested that this is not likely to hold if the deformation parameter is very variable over the Fermi surface, as is probable in the noble metals, and that the oscillations may then indicate the positions of parts of high deformability.

Ultrasonic attenuation at 500 kHz in superconducting tin

1969 ◽  
Vol 309 (1497) ◽  
pp. 259-280 ◽  
Keyword(s):  
Fermi Surface ◽  
Free Path ◽  
Phonon Scattering ◽  
Ultrasonic Attenuation ◽  
Mean Free Path ◽  
Attenuation Curve ◽  
Anisotropic Superconductor ◽  
Gap Anisotropy ◽  
Heavily Doped ◽  
Good Agreement

The temperature dependence of the longitudinal ultrasonic attenuation in single crystals of white tin has been measured by a resonance technique at a frequency of 500 kHz between 1 and 4.2 °K, for propagation along (100) and (001). The resistance ratio of the samples varied from 800 to 30000 and in all cases the electronic mean free path is smaller than the ultrasonic wavelength. No difference is found between propagation along (100) and (001) in the most heavily doped samples, in contrast to the suggestion of Kadanoff & Pippard, although in this case the normalized attenuation curve lies above the form found by Bardeen, Cooper & Schrieffer (B.C.S.). A systematic decrease of attenuation with increasing purity is found, so that in the most pure samples the curve lies well below the B.C.S. form. This effect is more marked for (001) propagation. A simple model is used to calculate the details of elastic scattering in the anisotropic superconductor, and it is shown that scattering across the Fermi surface can account for the lack of any orientational differences. The free path of the excitations is modified by the anisotropy: this brings the theory into very good agreement with the present results, and also increases the theoretical anisotropy of thermal conductivity in tin so as to agree with experiment. Phonon scattering across the Fermi surface is shown to account for the variation of attenuation with purity; the anisotropy of this effect is consistent with the gap anisotropy.

Ultrasonic attenuation in white tin crystals

1967 ◽  
Vol 297 (1450) ◽  
pp. 408-423 ◽  
Keyword(s):  
Fermi Surface ◽  
Energy Gap ◽  
Ultrasonic Attenuation ◽  
Propagation Direction ◽  
Frequency Range ◽  
Weighted Averages ◽  
Conduction Electrons ◽  
Energy Gaps ◽  
Surface Measurements ◽  
Gap Parameter

A detailed study of the temperature dependence of the longitudinal ultrasonic attenuation in single crystals of white tin is presented. Measurements have been made at temperatures from 0⋅8 to 4⋅2°K on pure and impure samples in the frequency range 40 to 290 Mc/s, corresponding to ql e values 0⋅45 to 90, where q is the ultrasonic wave vector and l e the free path of the conduction electrons. For high ql e an energy gap parameter A = 2∆(0)/ kT c is measured as an average over a narrow effective zone of the Fermi surface. For propagation along <001>, A = 3⋅15 ± 0⋅04; along <310>, A = 4⋅24 ± 0⋅04; along <100>, A = 3⋅55 ± 0⋅04; along <110>, A = 3⋅84 ± 0⋅07. The results are interpreted by assigning different energy gaps to different zones of the Fermi surface. Measurements with ql e ~ 0⋅5 yield A = 3⋅47 ± 0⋅06, independent of the propagation direction, showing that the effective zone extends to the whole Fermi surface for such low ql e . A simple two-gap model of a superconductor is used to show that the gaps measured here are weighted averages over an effective zone, and not minima. At lower temperatures the attenuation is shown to depend on the minimum gap, in agreement with the analysis of Privorotskii, but to be negligibly small for tin.

Angular magnetoresistance oscillations and the shape of the Fermi surface in ?(ET)2IBr2

1992 ◽  
Vol 2 (1) ◽  
pp. 89-99 ◽  
Author(s):  
M. V. Kartsovnik ◽  
V. N. Laukhin ◽  
S. I. Pesotskii ◽  
I. F. Schegolev ◽  
V. M. Yakovenko
Keyword(s):  
Fermi Surface ◽  
Magnetoresistance Oscillations

Fermi-surface reconstruction close to a pressure-induced metal-insulator transition

2004 ◽  
Vol 114 ◽  
pp. 277-281 ◽  
Author(s):  
J. Wosnitza ◽  
J. Hagel ◽  
O. Stockert ◽  
C. Pfleiderer ◽  
J. A. Schlueter ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Surface Reconstruction ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Fermi Surface Reconstruction

ULTRASONIC ATTENUATION DUE TO ZENER RELAXATION IN SINGLE-CRYSTAL PALLADIUM HYDRIDE

1983 ◽  
Vol 44 (C9) ◽  
pp. C9-419-C9-424
Author(s):  
R. G. Leisure ◽  
T. Kanashiro ◽  
P. C. Riedi ◽  
D. K. Hsu
Keyword(s):  
Single Crystal ◽  
Ultrasonic Attenuation ◽  
Palladium Hydride
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