# Thickness dependent electronic structure in WTe$_2$ thin films

## TL;DR

This study investigates how reducing the thickness of WTe$_2$ thin films from 26 nm to 11 nm causes a transition from 3D to 2D electronic behavior, affecting quantum oscillations, Fermi pockets, and magnetoresistance.

## Contribution

It provides experimental evidence of a 3D to 2D crossover in WTe$_2$ thin films and shows how quantum oscillations and magnetoresistance evolve with thickness and gating.

## Key findings

- Crossover from 3D to 2D electronic behavior below 26 nm.
- Fermi pockets decrease in size with thinner samples.
- Quadratic magnetoresistance also transitions from 3D to 2D with thickness.

## Abstract

We study the electronic structure of WTe$_2$ thin film fakes with different thickness down to 11 nm. Angle-dependent quantum oscillations reveal a crossover from a three-dimensional (3D) to a two-dimensional (2D) electronic system when the sample thickness is reduced below 26 nm. The quantum oscillations further show that the Fermi pockets get smaller as the samples are made thinner, indicating that the overlap between conduction and valence bands is getting smaller and implying the spatial confinement could lift the overlap in even thinner samples. In addition, the quadratic magnetoresistance (MR) also shows a crossover from 3D to 2D behavior as the samples are made thinner, while gating is shown to affect both the quadratic MR and the quantum oscillations of a thin sample by tuning its carrier density.