Electron<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>g</mml:mi></mml:math>-factor anisotropy in an AlAs quantum well probed by ESR

Abstract

Electron spin resonance (ESR) was studied in an asymmetrically doped 16-nm AlAs quantum well grown in the [001] direction. Surprisingly the ESR was detectable even if the magnetic field was parallel to the surface of the two-dimensional system. This allowed us to investigate precisely the in-plane anisotropy of the electron $g$ factor. In the case of the magnetic field aligned along the [110] or $[1\overline{1}0]$ crystallographic axes only one ESR peak was observed, whereas it tended to split into two well-separated peaks when the in-plane component of the magnetic field was between these directions. This fact clearly indicates that two in-plane valleys at $X$ points of the Brillouin zone were occupied with electrons and each valley was characterized by the anisotropic $g$ factor with the [100], [010], and [001] principal axes. The principal $g$-factor values were extracted.