Magnetointersubband resistance oscillations in GaAs quantum wells placed in a tilted magnetic field

摘要

The magnetotransport of highly mobile two-dimensional electrons in wide GaAs single quantum wells with three populated subbands placed in tilted magnetic fields is studied. The bottoms of the lower two subbands have nearly the same energy while the bottom of the third subband has a much higher energy (E-1 approximate to E-2 E-3). At zero in-plane magnetic fields, magnetointersubband oscillations (MISO) between the ith and j th subbands are observed and obey the relation Delta(ij) = E-j - E-i = k (h) over bar omega(c), where omega(c) is the cyclotron frequency and k is an integer. An application of in-plane magnetic field produces dramatic changes in MISO and the corresponding electron spectrum. Three regimes are identified. At (h) over bar omega(c) Delta(12), the in-plane magnetic field increases considerably the gap Delta(12), which is consistent with the semiclassical regime of electron propagation. In contrast, at strong magnetic fields (h) over bar omega(c) Delta(12) relatively weak oscillating variations of the electron spectrum with the in-plane magnetic field are observed. At (h) over bar omega(c) approximate to Delta(12), the electron spectrum undergoes a transition between these two regimes through magnetic breakdown. In this transition regime MISO with odd quantum number k terminate, while MISO corresponding to even k evolve continuously into the high-field regime corresponding to (h) over bar omega(c) Delta(12).