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

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.

References in corpus (6)

• Chiral tunneling and the Klein paradox in graphene
• Quantum interference and Klein tunneling in graphene heterojunctions
• Selective transmission of Dirac electrons and ballistic magnetoresistance of \textit{n-p} junctions in graphene
• Quantum transport evidence for a three-dimensional Dirac semimetal phase in Cd3As2
• Magnetic confinement of massless Dirac fermions in graphene
• Linear magnetoresistance caused by mobility fluctuations in the n-doped Cd3As2

Cited by in corpus (1)

• Photonic Dirac Nodal Line Semimetals Realized by Hyper-crystal