Temperature Damping of Magneto-Intersubband Resistance Oscillations in Magnetically Entangled Subbands

Magneto-intersubband resistance oscillations (MISOs) of highly mobile 2D electrons in symmetric GaAs quantum wells with two populated subbands are studied in magnetic fields tilted from the normal to the 2D electron layer at different temperatures $T$. A decrease of MISO amplitude with temperature increase is observed. At moderate tilts, the temperature decrease of MISO amplitude is consistent with a decrease of the Dingle factor due to a reduction of the quantum electron lifetime at high temperatures. At large tilts, a different regime of strong MISO suppression with the temperature is observed. The proposed model relates this suppression to magnetic entanglement between subbands, leading to beating in oscillating density of states. The model yields corresponding temperature damping factor: ${A}_{\text{MISO}}(T)=X/sinh(X)$, where $X=2{\ensuremath{\pi}}^{2}kT\ensuremath{\delta}f$ and $\ensuremath{\delta}f$ is the difference frequency of oscillations of density of states in two subbands. This factor is in agreement with experiments. A Fermi liquid enhancement of MISO amplitude is observed.