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Thermal E.M.F. Anomalies Due to Axial Compression and the Band Structure of Bi 1‐ x Sb x ( x = 0.27) Alloys
Author(s) -
Brandt N. B.,
Lavrenyuk M. Yu.,
Mini. Ya.,
Savin A. M.,
Kraak W.,
Herrmann R.
Publication year - 1987
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221430220
Subject(s) - condensed matter physics , dumbbell , saddle point , magnetoresistance , fermi surface , deformation (meteorology) , materials science , electron , fermi level , crystal (programming language) , oscillation (cell signaling) , physics , magnetic field , geometry , chemistry , composite material , medicine , biochemistry , mathematics , superconductivity , quantum mechanics , computer science , programming language , physical therapy
The electron Fermi surface (FS) in single‐crystal Bi 0.73 Sb 0.27 alloys and its change under axial compression are investigated with the help of magnetoresistance quantum oscillations. An additional frequency in the oscillation picture due to the minimum FS cross sections is observed. This is consistent with the assumption that the FS in the unstrained alloy investigated consists of three dumbbell‐shaped pockets. When the specimen is compressed the maximum FS cross‐section abruptly decreases by a factor of two at some critical deformation ϵ cr . This phenomenon indicates that the “neck” of the dumbbell‐shaped FS disrupts at the moment when under compression the Fermi level crosses the saddle point of the energy spectrum. In the vicinity of the singular point the strain dependences of thermal e.m.f. and resistance reveal an anomalous behaviour what is a manifestation of the electronic topological transition.