On The Origin Of Beat Patterns In The Quantum Magneto-Resistance Of Gated Inas/Gasb And Inas/Alsb Quantum Wells
Abstract
It is commonly assumed that the beat patterns observed in the quantum magneto-resistance (QMR) of many semiconductor heterostructures are due to the presence of two Shubnikov-de Haas (SdH) series of slightly differing periods. The appearance of a second series is attributed to a 'Zero Field Spin Splitting' arising from a Rashba type of asymmetry. We present QMR measurements on gated InAs/GaSb quantum wells over an extended temperature range, 0.4 K < T < 31 K. At high carrier concentrations, a beating is observed which arises from a mixing of the first subband SdH series and a magneto-intersubband oscillation, the onset of which occurs when the Fermi energy is close to the bottom of the second subband. It is only at the lowest concentrations where the well asymmetry is minimal that beat patterns due to two narrowly split SdH series are observed. In contrast, no beating is found in gated InAs/AlSb wells at 4.2K over a very large concentration range (4.8×10^11 cm-2 < n < 2.4× 10^12 cm-2).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2001
- Bibcode:
- 2001APS..MARG25004S