Modification of the energy spectrum and magnetic breakdown in a system of 2D holes at the GaAs/Al0.5 Ga0.5As heterojunction upon uniaxial compression

Uniaxial compression of the p-type GaAs/Al_0.5Ga_0.5 As heterostructures induces magnetic breakdown between the spin-split ground-state subbands of two-dimensional heavy holes. This phenomenon serves as direct experimental evidence of a strong qualitative modification of the energy spectrum of these structures upon uniaxial deformation. This modification has been revealed by numerical calculations, and, according to it, the subband spin splitting decreases upon compression, while the contours of the hole Fermi surface in both subbands touch one another in the compression direction in a pressure range of 2.5 kbar.