Canted Antiferromagnetic Phase in a Double Quantum Well in a Tilted Quantizing Magnetic Field

V. S. Khrapai, E. V. Deviatov, A. A. Shashkin, and V. T. Dolgopolov.
Institute of Solid State Physics, Chernogolovka, Moscow District 142432, Russia ;
F. Hastreiter and A. Wixforth.
Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1,D-80539 München, Germany ;
K. L. Campman and A. C. Gossard.
Materials Department and Center for Quantized Electronic Structures, University of California, Santa Barbara, California 93106

Physical Review Letters -- January 24, 2000 -- Volume 84, Issue 4 pp. 725-728

We investigate the double-layer electron system in a parabolic quantum well at filling factor n = 2 in a tilted magnetic field using capacitance spectroscopy. The competition between two ground states is found at the Zeeman splitting appreciably smaller than the symmetric-antisymmetric splitting. Although at the transition point the system breaks up into domains of the two competing states, the activation energy turns out to be finite, signaling the occurrence of a new insulator-insulator quantum phase transition. We interpret the obtained results in terms of a predicted canted antiferromagnetic phase.

KeyWords: semiconductor quantum wells; magnetic field effects; antiferrimagnetism; capacitance; ground states; Zeeman effect; spontaneous symmetry breaking; phase transformations

URL: http://link.aps.org/abstract/PRL/v84/p725
Abstract   Full Text:   [ PDF (70 kB) ]   Additional Information