# Anomalous thermoelectric properties of a Floquet topological insulator with spin momentum non-orthogonality

## TL;DR

This paper investigates how spin momentum non-orthogonality in 3D topological insulators affects their thermoelectric properties, revealing a momentum-dependent gap induced by off-resonant light and a resulting topological transition.

## Contribution

It introduces the impact of spin momentum non-orthogonality on thermoelectric behavior and demonstrates the momentum-dependent gap and topological transition caused by off-resonant light.

## Key findings

- Momentum-dependent gap causes topological transition.
- Unusual double peak structure in Nernst and electrical conductivities.
- Off-resonant light induces a momentum-dependent gap.

## Abstract

The spin momentum non-orthogonality in 3D topological insulators leads to modification of the spin texture and brings in an out-of-plane spin polarization component. Apart from spin texture, the anomalous thermoelectric properties of these materials are worth studying. In this paper, we have pointed out that the off resonant light used to irradiate the surface states, induces a gap, which becomes momentum dependent due to the presence of non-orthogonal terms in the Hamiltonian. Importantly, to maintain the off resonant condition of light, the momentum value should satisfy a bound. Furthermore, the momentum dependent gap causes a topological transition at higher value of momentum, which is important to analyse the unusual double peak structure of the Nernst and electrical conductivities.