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 characte ristics of GaSb-AlSb double-barrier heterostructures at 4 K and under a hydrostatic pressure of 7 kbar. We explain this phenomenon by the ac cumulation of electrons in the L-point valley of the GaSb quantum well , after they tunnel from the electrode to a Gamma-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, i s confirmed with magnetotunneling experiments up to 20 T. At this fiel d, bistability completely disappears because of the field-induced redu ction of Gamma-L scattering.