Chaos-Assisted Dynamical Tunneling in Flat Band Superwires

TL;DR

This paper explores how chaos-assisted dynamical tunneling occurs in flat band superwires within two-dimensional superlattices, revealing mechanisms for controlled tunneling in quantum transport systems.

Contribution

It introduces a theoretical framework for chaos-assisted dynamical tunneling in flat band superwires, linking classical phase space dynamics with quantum tunneling phenomena.

Findings

Dynamical tunneling links disjoint phase space regions in superwires.

Superwires are mainly found within flat bands from degenerate Bloch states.

Tunneling rates can be controlled and suppressed in various lattice configurations.

Abstract

Recent theoretical investigations have revealed unconventional transport mechanisms within high Brilliouin zones of two-dimensional superlattices. Electrons can navigate along channels we call superwires, gently guided without brute force confinement. Such dynamical confinement is caused by weak superlattice deflections, markedly different from the static or energetic confinement observed in traditional wave guides or one-dimensional electron wires. The quantum properties of superwires give rise to elastic dynamical tunneling, linking disjoint regions of the corresponding classical phase space, and enabling the emergence of several parallel channels. This paper provides the underlying theory and mechanisms that facilitate dynamical tunneling assisted by chaos in periodic lattices. Moreover, we show that the mechanism of dynamical tunneling can be effectively conceptualized through the lens of a paraxial approximation. Our results further reveal that superwires predominantly exist within flat bands, emerging from eigenstates that represent linear combinations of conventional degenerate Bloch states. Finally, we quantify tunneling rates across various lattice configurations, and demonstrate the tunneling can be suppressed in a controlled fashion, illustrating potential implications in future nanodevices.