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Commensurate-incommensurate transitions of quantum Hall stripe states in double-quantum-well systems

R. Cote·H. A. Fertig·J. Bourassa·D. Bouchiha
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Abstract

In higher Landau levels (N>0) and around filling factors nu =4N+1, a two-dimensional electron gas in a double-quantum-well system supports a stripe groundstate in which the electron density in each well is spatially modulated. When a parallel magnetic field is added in the plane of the wells, tunneling between the wells acts as a spatially rotating effective Zeeman field coupled to the ``pseudospins'' describing the well index of the electron states. For small parallel fields, these pseudospins follow this rotation, but at larger fields they do not, and a commensurate-incommensurate transition results. Working in the Hartree-Fock approximation, we show that the combination of stripes and commensuration in this system leads to a very rich phase diagram. The parallel magnetic field is responsible for oscillations in the tunneling matrix element that induce a complex sequence of transitions between commensurate and incommensurate liquid or stripe states. The homogeneous and stripe states we find can be distinguished by their collective excitations and tunneling I-V, which we compute within the time-dependent Hartree-Fock approximation.

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R. Cote, H. A. Fertig, J. Bourassa, D. Bouchiha. 2002-07-02. Commensurate-incommensurate transitions of quantum Hall stripe states in double-quantum-well systems. https://doi.org/10.1103/physrevb.66.205315

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