Split-Channel Ballistic Transport in an InSb Nanowire

• Published in: Nano letters Vol. 18; no. 4; pp. 2282 - 2287
• Main Authors: Estrada Saldaña, Juan Carlos, Niquet, Yann-Michel, Cleuziou, Jean-Pierre, Lee, Eduardo J. H, Car, Diana, Plissard, Sébastien R, Bakkers, Erik P. A. M, De Franceschi, Silvano
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11-04-2018
• Subjects: Chemical Sciences; Condensed Matter; Cristallography; Material chemistry; Materials Science; Physics; Quantum Physics; band structure; one-dimensional transport; helical liquid; Majorana fermions; Conductance quantization; nanowire
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.7b03854

We report an experimental study of one-dimensional (1D) electronic transport in an InSb semiconducting nanowire. A total of three bottom gates are used to locally deplete the nanowire, creating a ballistic quantum point contact with only a few conducting channels. In a magnetic field, the Zeeman splitting of the corresponding 1D sub-bands is revealed by the emergence of conductance plateaus at multiples of e 2/h, yet we find a quantized conductance pattern largely dependent on the configuration of voltages applied to the bottom gates. In particular, we can make the first plateau disappear, leaving a first conductance step of 2e 2/h, which is indicative of a remarkable 2-fold sub-band degeneracy that can persist up to several tesla. For certain gate voltage settings, we also observe the presence of discrete resonant states producing conductance features that can resemble those expected from the opening of a helical gap in the sub-band structure. We explain our experimental findings through the formation of two spatially separated 1D conduction channels.