# Molecular beam epitaxy of three-dimensionally thick Dirac semimetal Cd3As2 films

## TL;DR

This paper reports the successful growth of high-mobility, three-dimensional thick Cd3As2 films via molecular beam epitaxy, revealing unique quantum transport phenomena including Hall plateau-like structures and unconventional magnetic orbits.

## Contribution

It introduces a method to produce high-quality 3D Cd3As2 films with low carrier density and high mobility, enabling new insights into their quantum transport properties.

## Key findings

- Achieved highest electron mobility of 3×10^4 cm^2/Vs in 3D Cd3As2 films.
- Observed Hall plateau-like structures in thick films despite their 3D nature.
- Detected unconventional magnetic orbits distinct from semiclassical Weyl-orbit predictions.

## Abstract

Rapid progress of quantum transport study in topological Dirac semimetal, including observations of quantum Hall effect in two-dimensional (2D) Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ samples, has uncovered even more interesting quantum transport properties in high-quality and three-dimensional (3D) samples. However, such 3D Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films with low carrier density and high electron mobility have been hardly obtained. Here we report the growth and characterization of 3D thick Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films adopting molecular beam epitaxy. The highest electron mobility ($\mu$ = 3 $\times$ 10$^{4}$ cm$^{2}$/Vs) among the reported film samples has been achieved at a low carrier density ($\textit{n} = 5$ $\times$ 10$^{16}$ cm$^{-3}$). In the magnetotransport measurement, Hall plateau-like structures are commonly observed in spite of the 3D thick films ($\textit{t} = 120$ nm). On the other hand, field angle dependence of the plateau-like structures and corresponding Shubunikov-de Haas oscillations rather shows a 3D feature, suggesting the appearance of unconventional magnetic orbit, also distinct from the one described by the semiclassical Weyl-orbit equation.