ABSTRACT
The development of magnetic breakdown in two-dimensional hole system under uniaxial compression P has been detected for the first time in p-GaAs/Al0.5Ga0.5As heterostructures. The phenomenon reveals in complications of the Fourier transform spectra of Subnikov-de Haas quantum oscillations under compression and indicates 2D hole tunneling through a semiclassically forbidden small energy gap εg between two different spin-split subbands of the heavy hole ground state in a sufficiently strong magnetic field. The magnetic breakdown development confirms the specific character of the Fermi surface transformation in spin-split subbands under uniaxial compression: according to the performed numerical calculations at P = 2, 5 Kbar the value εg = 0 in the direction of compression and remains to be very small at P > 2, 5 Kbar. So the characteristic interband magnetic breakdown field HB ~ εg also drops almost to zero.
