Quantum confinement of the Dirac surface states in topological-insulator nanowires

Abstract

The non-trivial topology of the three-dimensional (3D) topological insulator (TI) dictates the appearance of gapless Dirac surface states. Intriguingly, when a 3D TI is made into a nanowire, a gap opens at the Dirac point due to the quantum confinement, leading to a peculiar Dirac sub-band structure. This gap is useful for, e.g., future Majorana qubits based on TIs. Furthermore, these Dirac sub-bands can be manipulated by a magnetic flux and are an ideal platform for generating stable Majorana zero modes (MZMs), which play a key role in topological quantum computing. However, direct evidence for the Dirac sub-bands in TI nanowires has not been reported so far. Here we show that by growing very thin ($\sim$40-nm diameter) nanowires of the bulk-insulating topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ and by tuning its chemical potential across the Dirac point with gating, one can unambiguously identify the Dirac sub-band structure. Specifically, the resistance measured on gate-tunable four-terminal devices was found to present non-equidistant peaks as a function of the gate voltage, which we theoretically show to be the unique signature of the quantum-confined Dirac surface states. These TI nanowires open the way to address the topological mesoscopic physics, and eventually the Majorana physics when proximitised by an $s$-wave superconductor.

arXiv comment7 pages main text, 6 pages supplemental material

References in corpus (27)

• Non-Abelian Anyons and Topological Quantum Computation
• New directions in the pursuit of Majorana fermions in solid state systems
• Topological Insulator Materials
• Aharonov-Bohm interference in topological insulator nanoribbons
• Band structure engineering in (Bi1-xSbx)2Te3 ternary topological insulators
• Observation of Dirac Holes and Electrons in a Topological Insulator
• Majorana Fermions in Proximity-coupled Topological Insulator Nanowires
• Gate capacitance of back-gated nanowire field-effect transistors
• Ultra-low carrier concentration and surface dominant transport in Sb-doped Bi2Se3 topological insulator nanoribbons
• Aharonov-Bohm oscillations in disordered topological insulator nanowires
• Planar Hall effect from the surface of topological insulators
• Anomalous Aharonov-Bohm conductance oscillations from topological insulator surface states
• One-dimensional helical transport in topological insulator nanowire interferometers
• Aharonov-Bohm Oscillations in a Quasi-Ballistic 3D Topological Insulator Nanowire
• Magnetic field induced helical mode and topological transitions in a quasi-ballistic topological insulator nanoribbon with circumferentially quantized surface state sub-bands
• Gigantic negative magnetoresistance in a disordered topological insulator
• Probing Spin Helical Surface States in Topological HgTe Nanowires
• Majorana qubits in topological insulator nanoribbon architecture
• Revealing puddles of electrons and holes in compensated topological insulators
• Charge puddles in the bulk and on the surface of the topological insulator BiSbTeSe${}_2$ studied by scanning tunneling microscopy and optical spectroscopy
• Quantum confinement of the Dirac surface states in topological-insulator nanowires
• Pseudo-ballistic transport in 3D topological insulator quantum wires
• Ambipolar Surface Conduction in Ternary Topological Insulator Bi_2(Te_{1-x}Se_x)_3 Nanoribbons
• Bulk-Free Topological Insulator Bi2Se3 nanoribbons with Magnetotransport Signatures of Dirac Surface States
• FIB synthesis of Bi2Se3 1D nanowires demonstrating the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance
• Hyers-Ulam stability of elliptic Möbius difference equation
• Length scale of puddle formation in compensation-doped semiconductors and topological insulators

Cited by in corpus (19)

• Opportunities in topological insulator devices
• Superconducting diode effect due to magnetochiral anisotropy in topological insulator and Rashba nanowires
• Giant magnetochiral anisotropy from quantum confined surface states of topological insulator nanowires
• Quantum confinement of the Dirac surface states in topological-insulator nanowires
• Spin-resolved thermal signatures of Majorana-Kondo interplay in double quantum dots
• Majorana bound states in topological insulators without a vortex
• Proximity-induced superconductivity in (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ topological-insulator nanowires
• Top-down fabrication of bulk-insulating topological insulator nanowires for quantum devices
• Metallization and proximity superconductivity in topological insulator nanowires
• Robust and fragile Majorana bound states in proximitized topological insulator nanoribbons
• Finite-size effects in cylindrical topological insulators
• Characterizing the chemical potential disorder in the topological insulator (Bi${}_{1-x}$Sb${}_x$)${}_2$Te${}_3$ thin films
• Electrostatic effects of the MnBi2Te4-superconductor hetero-structures in chiral Majorana search
• Fabry-Pérot interferometry with gate-tunable 3D topological insulator nanowires
• Anisotropic transport properties in prismatic topological insulator nanowires
• Aharanov-Bohm oscillations and perfectly transmitted mode in amorphous topological insulator nanowires
• Electronic confinement of surface states in a topological insulator nanowire
• Electromagnetic response of the surface states of a topological insulator nanowire embedded within a resonator
• Equatorial magnetoplasma waves