Opportunities in topological insulator devices

Abstract

Topological insulators are expected to be a promising platform for exciting quantum phenomena, whose experimental realizations require sophisticated devices. However, topological-insulator materials are generally more delicate than conventional semiconductor materials and the fabrication of high-quality devices has been a challenge. In this Expert Recommendation, we discuss the nature of this challenge and present useful tips for successful device fabrications, taking superconducting and ferromagnetic devices as concrete examples. We also recommend some promising future directions.

Disorder effects in topological insulator nanowires

“…Recently, substantial experimental progresses has been made in thin TI nanowires and nanoribbons, where all mobile electrons (holes) are located at the wire sufrace [17][18][19][20][21][22][23][24][25][26][27]. They attract attention because the Dirac spectrum of surface electrons (holes) splits in equidistant surface subbands sepa-rated by the substantial gap ∆ due to the small wire crosssection perimeter.…”

Giant magnetochiral anisotropy from quantum confined surface states of topological insulator nanowires

“…Experiment. To experimentally investigate the predicted non-reciprocal transport behaviour, we fabricated nanowire devices 15 of the bulk-insulating TI material (Bi 1−x Sb x ) 2 Te 3 as shown in Fig. 1a by etching highquality thin films grown by molecular beam epitaxy (MBE).…”

“…TI nanowire devices are still in their infancy 15 and so the size of MCA could be increased, perhaps substantially, with future improvements in nanowire quality that will enable an increase of the relevant energy scales closer to the theoretical limit. In principle, the temperature at which giant MCA in TI nanowires is observable is limited only by the subband gap, which is larger in thinner/narrower nanowires.…”