Enhanced third harmonic response of the PtTe$_2$ transition metal dichalcogenide

TL;DR

This study analyzes the third harmonic nonlinear optical response of PtTe$_2$, revealing that its topological properties and Dirac cone tilting significantly enhance its nonlinear susceptibility, with implications for nanophotonic device applications.

Contribution

It provides an analytical calculation of the nonlinear conductivity in PtTe$_2$ based on a low-energy model fitted from DFT, highlighting the impact of Dirac cone tilting on nonlinear optical properties.

Findings

Third-order nonlinearities are significantly enhanced by cone tilting.

The nonlinear susceptibility can be modulated by the material's topological features.

Results are relevant for designing tunable nanophotonic devices.

Abstract

We investigate the third harmonic response of platinum ditelluride (PtTe$_2$), a Dirac semimetal belonging to the transition metal dichalcogenides class. Due to its topological properties, this material has drawn a lot of attention, particularly because it hosts type-II (super-critically tilted) Dirac fermions in the $\rm A-\Gamma-\rm A$ high symmetry direction. Adopting a low-energy model fitted directly from density functional theory band structure simulations, we calculate analytically the nonlinear conductivity. We observe that third-order optical nonlinearities are efficiently modulated by the cones tilting, which produces a significant enhancement of the nonlinear susceptibility. Our results, besides shedding light on topological transitions of platinum ditelluride, are relevant for future nanophotonic devices exploiting the tunable nonlinear properties of type-II Dirac fermions.