Effect of quantum Hall edge strips on valley splitting in silicon quantum wells
article
We determine the energy splitting of the conduction-band valleys in two-dimensional electrons confined to low-disorder Si quantum wells. We probe the valley splitting dependence on both perpendicular magnetic field B and Hall density by performing activation energy measurements in the quantum Hall regime over a large range of filling factors. The mobility gap of the valley-split levels increases linearly with B and is strikingly independent of Hall density. The data are consistent with a transport model in which valley splitting depends on the incremental changes in density eB/h across quantum Hall edge strips, rather than the bulk density. Based on these results, we estimate that the valley splitting increases with density at a rate of 116 µeV/1011cm−2 , consistent with theoretical predictions for near-perfect quantum well top interfaces.
TNO Identifier
884266
Source
Physical review letters, 125(18)
Publisher
American Physical Society APS
Article nr.
186801
Collation
5 p.
Place of publication
College Park, MD, USA
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