Tunable valley filtering in dynamically strained a-T3 lattices

Mechanical deformations in alpha-T-3 lattices induce local pseudomagnetic fields of opposite directionality for different valleys. When this strain is equipped with a dynamical drive, it generates a complementary valley -asymmetric pseudoelectric field, which is expected to accelerate electrons. We propose that by combining these effects by a time-dependent nonuniform strain, tunable valley filtering devices can be engineered that extend beyond the static capabilities. We demonstrate this by implementing an oscillating Gaussian bump centered in a four-terminal Hall bar alpha-T-3 setup and calculating the induced pseudoelectromagnetic fields analytically. Within a recursive Floquet Green-function scheme, we determine the time-averaged transmission and valley polarization, as well as the spatial distributions of the local density of states and current density. As a result of the periodic drive, we detect novel energy regimes with a highly valley-polarized transmission, depending on alpha. Analyzing the spatial profiles of the time-averaged local density of states and current density we can relate these regimes to the pseudoelectromagnetic fields in the setup. By means of the driving frequency, we can manipulate the valley-polarized states, which might be advantageous for future device applications.

Automated summary

Mechanical deformations and dynamical drive are combined to design a tunable valley filtering device in α-T-3 lattices. Periodic strain generates valley-polarized transmission, which can be controlled by driving frequency.