Quantum transport in an ambipolar InSb nanowire quantum dot device

TL;DR

This paper reports on quantum transport measurements in an InSb nanowire quantum dot device, demonstrating tunable electron and hole regimes with detailed analysis of quantum levels and lead states, advancing spintronics and quantum device research.

Contribution

The study introduces a high-quality InSb nanowire quantum dot device capable of switching between electron and hole regimes, with a novel tomographic method for analyzing lead states.

Findings

Observation of dozens of quantum levels without charge rearrangement

Detection of Coulomb blockade, Zeeman, and Kondo effects in electron regime

Identification and analysis of conductance peaks from lead states in hole regime

Abstract

Semiconductor InSb nanowires present a highly intriguing platform with immense potential for applications in spintronics and topological quantum devices. The narrow band gap exhibited by InSb allows for precise tuning of these nanowires, facilitating smooth transitions between the electron transport region and the hole transport region. In this study, we demonstrate quantum transport measurements obtained from a high-quality InSb nanowire quantum dot device. By utilizing a back gate, this device can be adjusted from an electron-populated quantum dot regime to a hole-populated one. Within both regimes, we have observed dozens of consecutive quantum levels without any charge rearrangement or impurity-induced interruptions. Our investigations in the electron transport regime have explored phenomena such as Coulomb blockade effect, Zeeman effect,and Kondo effect. Meanwhile, in the hole-transport regime, we have identified conductance peaks induced by lead states. Particularly, we have created a tomographic analysis method of these lead states by tracking the behavior of these conductance peaks across consecutive Coulomb diamond structures.