Plasmon geometric phase and plasmon Hall shift

TL;DR

This paper reveals how non-zero Hall conductivity in metals induces a complex internal structure in plasmons, leading to geometric phases and a non-reciprocal Hall shift that can be experimentally observed.

Contribution

It introduces the concept of plasmon geometric phase and demonstrates the plasmon Hall shift caused by Hall conductivity, enriching the understanding of plasmon dynamics.

Findings

Plasmons in Hall metals acquire geometric phases during scattering.

Boundary reflections cause a non-reciprocal plasmon shift along the boundary.

The plasmon Hall shift is tunable by Hall conductivity and wavelength.

Abstract

The collective plasmonic modes of a metal comprise a pattern of charge density and tightly-bound electric fields that oscillate in lock-step to yield enhanced light-matter interaction. Here we show that metals with non-zero Hall conductivity host plasmons with a fine internal structure: they are characterized by a current density configuration that sharply departs from that of ordinary zero Hall conductivity metals. This non-trivial internal structure dramatically enriches the dynamics of plasmon propagation, enabling plasmon wavepackets to acquire geometric phases as they scatter. Strikingly, at boundaries these phases accumulate allowing plasmon waves that reflect off to experience a non-reciprocal parallel shift along the boundary displacing the incident and reflected plasmon trajectories. This plasmon Hall shift, tunable by Hall conductivity as well as plasmon wavelength, displays the chirality of the plasmon's current distribution and can be probed by near-field photonics techniques. Anomalous plasmon dynamics provide a real-space window into the inner structure of plasmon bands, as well as new means for directing plasmonic beams.