Signatures of thermal hysteresis in Tamm-wave propagation

TL;DR

This study numerically investigates Tamm wave propagation at a VO2 interface, revealing how thermal hysteresis affects wave characteristics during heating and cooling cycles at optical wavelengths.

Contribution

It demonstrates the first numerical evidence of thermal hysteresis signatures in Tamm-wave propagation at a VO2 interface with multilayered dielectrics.

Findings

Distinct wavenumber differences during heating and cooling.

Clear demarcation of propagation distances based on thermal history.

Thermal hysteresis signatures are observable in Tamm-wave behavior.

Abstract

We numerically solved the boundary-value problem for Tamm waves (which may also be classified as Uller-Zenneck waves here) guided by the planar interface of a homogeneous isotropic dissipative dielectric (HIDD) material and a periodically multilayered isotropic dielectric material. The HIDD material was chosen to be VO${}_2$ which, at optical wavelengths, has a temperature-dependent refractive index with a hysteresis feature, i.e., the temperature-dependence of its refractive index varies depending upon whether the temperature is increasing or decreasing. A numerical code was implemented to extract solutions of the dispersion equation at a fixed wavelength for both $p$- and $s$-polarization states over the temperature range [50,80] degrees. A multitude of Tamm waves of both linear polarization states were found, demonstrating a clear demarcation of the heating and cooling phases in terms of wavenumbers and propagation distances. Thereby, the signatures of thermal hysteresis in Tamm-wave propagation were revealed.