Edge pseudo-magnetoplasmons

TL;DR

This paper investigates edge pseudo-magnetoplasmons in two-component electron systems with pseudomagnetic fields, revealing unique edge modes and potential applications in valleytronics and spintronics.

Contribution

It provides an exact solution for edge pseudo-magnetoplasmons in systems like strained graphene and Skyrmion lattices, uncovering new features absent in previous approximations.

Findings

Existence of two counter-propagating edge modes

Large pseudomagnetic fields lead to component-specific oscillations

Logarithmic divergence of plasmon velocity and no gapped edge modes inside the bulk gap

Abstract

We study the properties of edge plasmons in two-component electron liquids in the presence of pseudomagnetic fields, which have opposite signs for the two different electronic populations and therefore preserve the time-reversal symmetry. The physical realizations of such systems are many. We discuss the cases of strained graphene and of electrons in proximity to a Skyrmion lattice, solving the problem with the Wiener-Hopf technique. We show (i) that two charged counter-propagating acoustic edge modes exist at the boundary and (ii) that, in the limit of large pseudomagnetic fields, each of them involves oscillations of only one of the two electronic components. We suggest that the edge pseudo-magnetoplasmons of graphene can be used to selectively address the electrons of one specific valley, a feature relevant for the emerging field of valleytronics. Conversely, the spin-polarized plasmons at the boundary of Skyrmion lattices can be exploited for spintronics applications. Our solution highlights new features missing in previous (similar) results obtained with uncontrolled approximations, namely a logarithmic divergence of the plasmon velocity, and the absence of gapped edge modes inside the bulk-plasmon gap.