LOW-FREQUENCY SHOT-NOISE IN DOUBLE-BARRIER RESONANT-TUNNELING GAAS ALXGA1-XAS STRUCTURES IN A STRONG MAGNETIC-FIELD/

Low-frequency shot noise and de current profiles for a double-barrier resonant-tunnelling structure (DBRTS) under a strong magnetic field ap plied perpendicular to the interfaces have been studied. Structures wi th a 3D and 2D emitter have both been considered. The calculations, ca rried out with the Keldysh Green's function technique, show strong dep endencies of both the current and noise profiles on the bias voltage a nd magnetic field. The noise spectrum appears sensitive to charge accu mulation due to barrier capacitances, and both noise and de current ar e extremely sensitive to the Landau level broadening in the emitter el ectrode and can be used as a powerful tool to investigate the latter. As an example, two specific shapes of the level broadening have been c onsidered-a semi-elliptic profile resulting from the self-consistent B orn approximation, and a Gaussian one resulting from the lowest-order cumulant expansion.