Valley filtering in strain-induced $\alpha$-${\mathcal{T}}_3$ quantum dots

Abstract

We test the valley-filtering capabilities of a quantum dot inscribed by locally straining an $\alpha$-${\mathcal{T}}_3$ lattice. Specifically, we consider an out-of-plane Gaussian bump in the center of a four-terminal configuration and calculate the generated pseudomagnetic field having an opposite direction for electrons originating from different valleys, the resulting valley-polarized currents, and the conductance between the injector and collector situated opposite one another. Depending on the quantum dot's width and width-to-height ratio, we detect different transport regimes with and without valley filtering for both the $\alpha$-${\mathcal{T}}_3$ and dice lattice structures. In addition, we analyze the essence of the conductance resonances with a high valley polarization in terms of related (pseudo-) Landau levels, the spatial distribution of the local density of states, and the local current densities. The observed local charge and current density patterns reflect the local inversion symmetry breaking by the strain, besides the global inversion symmetry breaking due to the scaling parameter $\alpha$. By this way we can also filter out different sublattices.

8 pages, 5 figures, slightly corrected version

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Cited by in corpus (6)

• Strain-induced pseudo-magnetic field in $\alpha -{\mathcal{T}}_3$ lattice
• Dynamical optical conductivity for gapped $\alpha -{\mathcal{T}}_3$ materials with a curved "flat" band
• Tunable valley filtering in dynamically strained $\alpha$-${\mathcal{T}}_3$ lattices
• Thermal Transport Properties of Magnons on the $\alpha$-T${}_3$ Lattice
• Tunneling valley Hall effect induced by coherent geometric phase
• Singular flat bands in the modified Haldane-Dice model