Fizika Nizkikh Temperatur: Volume 45, Number 11 (November 2019), p. 1415-1422    ( to contents , go back )

Quantum effects in a germanium quantum well with ultrahigh carrier mobility

I.B. Berkutov1,2,3, V.V. Andrievsky1, Yu.A. Kolesnichenko1, and O.A. Mironov2,4

1B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauki Ave., Kharkiv 61103, Ukraine

2Institute of Low Temperature and Structure Research, Polish Academy of Sciences ul. Okólna 2, 50-422, Wrocław, Poland

3Department of Physics, North Carolina State University, Raleigh, NC 27695, USA

4Department of Physics, University of Warwick, Coventry CV4 7AL, UK
E-mail: ibercutov@gmail.com

Received July 3, 2019, published online September 27, 2019

Abstract

A complex study of quantum effects in the p-type Si0.2Ge0.8/Ge/Si0.2Ge0.8 heterostructure with extremely high carrier mobility μH = 1367000 cm2/(V∙s) has been carried out. The analysis of the Shubnikov–de Haas magneto-quantum oscillations made it possible to calculate the effective mass of charge carriers, which appear be very low, m* = 0.062m0, as well as the value of fluctuations of hole concentration along the channel, δp = = 3.5∙109 cm–2. In stronger magnetic fields, the manifestation of the fractional Hall effect with filling numbers of 8/3, 7/3, 5/3, 4/3, which occur at temperatures up to 5 K, was found. The studies of the quantum interference effects of weak localization and electron-electron interaction of charge carriers, that were carried out in such a highly mobile system for the first time, allowed us to calculate the spin splitting value Δ = 1.07 meV and the values of the electron-electron interaction constant F0σ=−0.12, which are comparable with the previously obtained results.

Key words: two-dimensional conductor, Shubnikov–de Haas effect, quantum interference effects, fractional Hall effect, magnetoresistance.

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