Intrinsic bistability by charge accumulation in an L-valley state in GaSb-AlSb resonant-tunneling diodes

We have observed intrinsic bistability in the current-voltage characteristics of GaSb-AlSb double-barrier heterostructures at 4 K and under a hydrostatic pressure of 7 kbar. We explain this phenomenon by the accumulation of electrons in the L-point valley of the GaSb quantum well, after they tunnel from the electrode to a Γ-point quantum state and then scatter into the L point. Our model, which takes into account the various scattering and tunneling times involved in the process, is confirmed with magnetotunneling experiments up to 20 T. At this field, bistability completely disappears because of the field-induced reduction of Γ-L scattering.