Weak antilocalization in gate-controlled Al/sub x/Ga/sub 1-x/N/GaN two-dimensional electron gases
ABSTRACT This version is available at http://link.aps.org/abstract/PRB/v73/e241311 Copyright © The American Physical Society Weak antilocalization and the Shubnikov–de Haas effect were investigated in AlxGa1–xN/GaN two-dimensional electron gases. The weak antilocalization measurements on a gated sample revealed a constant spin-orbit scattering length, which does not change if the Al content or the thickness of the AlxGa1–xN barrier layer is varied. The occurrence of spin-orbit coupling is assigned to the lack of crystal inversion symmetry. Although for some of the samples a beating pattern was observed in the Shubnikov–de Haas oscillations, its presence was not attributed to spin-orbit coupling but rather to inhomogeneities in the AlxGa1–xN barrier. The authors thank M. Marso ISG-1 for performing the CV measurements and H. Kertz ISG-1 for assistance during the low-temperature measurements. Fruitful discussions with R. Winkler Northern Illinois University and Yu. Lyanda-Geller Purdue University are gratefully acknowledged.