Acoustomagnetoelectric effect in two-dimensional materials: Geometric resonances and Weiss oscillations

We study electron transport in two-dimensional materials with parabolic and linear (graphene) dispersions of the carriers in the presence of surface acoustic waves and an external magnetic field using semiclassical Boltzmann equations approach. We observe an oscillatory behavior of both the longitudinal and Hall electric currents as functions of the surface acoustic wave frequency at a fixed magnetic field and as functions of the inverse magnetic field at a fixed frequency of the acoustic wave. We explain the former by the phenomenon of geometric resonances, while we relate the latter to the Weiss-like oscillations in the presence of the dynamic superlattice created by the acoustic wave. Thus we demonstrate the dual nature of the acoustomagnetoelectric effect in two-dimensional electron gas.

Figure 1

Proposed experimental setup: A two-dimensional electron gas (2DEG) with parabolic or linear (graphene) spectrum located on a piezoelectric substrate and exposed to a surface acoustic wave (SAW) with the wave vector $\mathbf{k}$ and an external permanent magnetic field $\mathbf{B}$. The SAW is created by the interdigital transducers (IDTs).

Figure 2

Electric current densities as functions of the SAW frequency for the parabolic dispersion case. (a) Longitudinal drag ($x$ component) and (b) Hall drag ($y$ component). Different colors correspond to different values of the applied magnetic field $B$, specified in panel (a).

Figure 3

Electric current densities as functions of the SAW frequency for the linear dispersion case. (a) Longitudinal drag ($x$ component) and (b) Hall drag ($y$ component). Different colors correspond to different values of the applied magnetic field $B$, specified in Fig. 2.

Figure 4

Components of electric current density as functions of inverse magnetic field in the case of parabolic dispersion for the frequencies specified in panel (a).

Figure 5

Components of electric current density as functions of inverse magnetic field in the case of linear dispersion for the frequencies specified in Fig. 4.