Fizika Nizkikh Temperatur: Volume 45, Number 11 (November 2019), p. 1391-1396    ( to contents , go back )

Spin-orbit coupling in strained Ge whiskers

A. Druzhinin, I. Ostrovskii, Y. Khoverko, and N. Liakh-Kaguy

Department of Semiconductor Electronics, Lviv Polytechnic National University, Lviv, Ukraine
E-mail: druzh@polynet.lviv.ua

Received April 5, 2019, published online September 27, 2019

Abstract

The field dependences of the magnetoresistance for germanium whiskers with gallium doping concentration of 2∙1017cm–3 were studied in the magnetic field range 0–14 T at temperature 4.2 K under compressive strain upto 0.2%. The strain influence on a spin-orbit splitting on the valence band spectrum was studied. As a result, the effective mass and the energies of spin-orbit splitting for light and heavy holes were found under the compressive strain according to kp method. From an analysis of the Shubnikov–de Haas magnetoresistance oscillations the effective mass of heavy holes mc = 0.25 m0 was calculated. The spin-orbit splitting energy of heavy holes ΔHH = 1.5 meV, the Lande factor in direction [111] g* = 4.8 as well as the Rashba cubic parameter of spin-orbit interaction βSO = 1∙10−28 eV∙m3 were found due to the studying of longitudinal magnetoconductance in strainedGe whiskers at low temperatures. The appearance of negative magnetoresistance in the magnetic field range up to 7 T likely results from the effect of charge carrier interaction.

Key words: germanium whiskers, magnetoresistance oscillations, electron-electron interaction, strain, cryogenic temperatures.

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