# Quantum dots formed in three-dimensional Dirac semimetal Cd$_3$As$_2$ nanowires

## TL;DR

This paper demonstrates the formation of quantum dots in Cd$_3$As$_2$ nanowires using electrostatic gating and magnetic fields, revealing Coulomb blockade and tunneling effects in a Dirac semimetal system.

## Contribution

It introduces a method to create and observe quantum dots in 3D Dirac semimetal nanowires, highlighting magnetic field-induced confinement and Coulomb blockade phenomena.

## Key findings

- Observation of Coulomb diamond features indicating single quantum dot formation
- Strong conductance suppression at the Dirac point under high magnetic fields
- Formation of p-n junctions acting as tunnel barriers due to cyclotron motion

## Abstract

We demonstrate quantum dot (QD) formation in three-dimensional Dirac semimetal Cd$_{3}$As$_{2}$ nanowires using two electrostatically tuned p$-$n junctions with a gate and magnetic fields. The linear conductance measured as a function of gate voltage under high magnetic fields is strongly suppressed at the Dirac point close to zero conductance, showing strong conductance oscillations. Remarkably, in this regime, the Cd$_{3}$As$_{2}$ nanowire device exhibits Coulomb diamond features, indicating that a clean single QD forms in the Dirac semimetal nanowire. Our results show that a p$-$type QD can be formed between two n$-$type leads underneath metal contacts in the nanowire by applying gate voltages under strong magnetic fields. Analysis of the quantum confinement in the gapless band structure confirms that p$-$n junctions formed between the p$-$type QD and two neighboring n$-$type leads under high magnetic fields behave as resistive tunnel barriers due to cyclotron motion, resulting in the suppression of Klein tunneling. The p$-$type QD with magnetic field-induced confinement shows a single hole filling. Our results will open up a route to quantum devices such as QDs or quantum point contacts based on Dirac and Weyl semimetals.