We have investigated 2D→2D magnetotunneling in a GaAs/AlAs "double barrier structure" with 20 Å AlAs layers separated by a 40 Å GaAs layer, as a function of hydrostatic pressure and in the presence of a magnetic field perpendicular to the interfaces (B∥J). At B=0 and at high pressures (≥10 kbar), resonant tunneling and its phonon satellites are observed between a Γ symmetry state in the GaAs emitter and a longitudinal Xz symmetry state in the AlAs collector. As the pressure is increased, the band offset between the Γ and the Xz states is decreased, resulting in a shift of these resonances to lower bias. At B≠0, clear periodic structures are observed in the current vs voltage characteristic, which are interpreted as resonant tunneling from the lowest emitter Γ Landau level to Xz collector levels of increasing Landau index. Quantitative analysis yields the energies of the phonons participating in the inelastic tunneling, and the transverse mass, mXY, at the band edge of AlAs. Our method provides the most accurate determination to date of the transverse mass, and reports on its pressure dependence. We find mXY/m0=[(0.284±0.008) - (0.0039±0.0003) × P] where P is the pressure in kbar.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - 15 Oct 2000