Symmetry protected Josephson supercurrents in three-dimensional topological insulators

Sungjae Cho, Brian Dellabetta, Alina Yang, John Schneeloch, Zhijun Xu, Tonica Valla, Genda Gu, Matthew J. Gilbert, Nadya Mason

Research output: Contribution to journalArticle

Abstract

Coupling the surface state of a topological insulator to an s-wave superconductor is predicted to produce the long-sought Majorana quasiparticle excitations. However, superconductivity has not been measured in surface states when the bulk charge carriers are fully depleted, that is, in the true topological regime relevant for investigating Majorana modes. Here we report measurements of d.c. Josephson effects in topological insulator-superconductor junctions as the chemical potential is moved through the true topological regime characterized by the presence of only surface currents. We compare our results with three-dimensional quantum transport simulations, and determine the effects of bulk/surface mixing, disorder and magnetic field; in particular, we show that the supercurrent is largely carried by surface states, due to the inherent topology of the bands, and that it is robust against disorder. Our results thus clarify key open issues regarding the nature of supercurrents in topological insulators.

Original languageEnglish (US)
Article number1689
JournalNature communications
Volume4
DOIs
StatePublished - May 20 2013

Fingerprint

Surface states
insulators
Superconducting materials
symmetry
Chemical potential
Magnetic Fields
Superconductivity
Charge carriers
disorders
Topology
Josephson effect
Magnetic fields
charge carriers
superconductivity
topology
magnetic fields
excitation
simulation

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Symmetry protected Josephson supercurrents in three-dimensional topological insulators. / Cho, Sungjae; Dellabetta, Brian; Yang, Alina; Schneeloch, John; Xu, Zhijun; Valla, Tonica; Gu, Genda; Gilbert, Matthew J.; Mason, Nadya.

In: Nature communications, Vol. 4, 1689, 20.05.2013.

Research output: Contribution to journalArticle

Cho, Sungjae ; Dellabetta, Brian ; Yang, Alina ; Schneeloch, John ; Xu, Zhijun ; Valla, Tonica ; Gu, Genda ; Gilbert, Matthew J. ; Mason, Nadya. / Symmetry protected Josephson supercurrents in three-dimensional topological insulators. In: Nature communications. 2013 ; Vol. 4.
@article{749466fe2315448ab39f9eecf8a12651,
title = "Symmetry protected Josephson supercurrents in three-dimensional topological insulators",
abstract = "Coupling the surface state of a topological insulator to an s-wave superconductor is predicted to produce the long-sought Majorana quasiparticle excitations. However, superconductivity has not been measured in surface states when the bulk charge carriers are fully depleted, that is, in the true topological regime relevant for investigating Majorana modes. Here we report measurements of d.c. Josephson effects in topological insulator-superconductor junctions as the chemical potential is moved through the true topological regime characterized by the presence of only surface currents. We compare our results with three-dimensional quantum transport simulations, and determine the effects of bulk/surface mixing, disorder and magnetic field; in particular, we show that the supercurrent is largely carried by surface states, due to the inherent topology of the bands, and that it is robust against disorder. Our results thus clarify key open issues regarding the nature of supercurrents in topological insulators.",
author = "Sungjae Cho and Brian Dellabetta and Alina Yang and John Schneeloch and Zhijun Xu and Tonica Valla and Genda Gu and Gilbert, {Matthew J.} and Nadya Mason",
year = "2013",
month = "5",
day = "20",
doi = "10.1038/ncomms2701",
language = "English (US)",
volume = "4",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",

}

TY - JOUR

T1 - Symmetry protected Josephson supercurrents in three-dimensional topological insulators

AU - Cho, Sungjae

AU - Dellabetta, Brian

AU - Yang, Alina

AU - Schneeloch, John

AU - Xu, Zhijun

AU - Valla, Tonica

AU - Gu, Genda

AU - Gilbert, Matthew J.

AU - Mason, Nadya

PY - 2013/5/20

Y1 - 2013/5/20

N2 - Coupling the surface state of a topological insulator to an s-wave superconductor is predicted to produce the long-sought Majorana quasiparticle excitations. However, superconductivity has not been measured in surface states when the bulk charge carriers are fully depleted, that is, in the true topological regime relevant for investigating Majorana modes. Here we report measurements of d.c. Josephson effects in topological insulator-superconductor junctions as the chemical potential is moved through the true topological regime characterized by the presence of only surface currents. We compare our results with three-dimensional quantum transport simulations, and determine the effects of bulk/surface mixing, disorder and magnetic field; in particular, we show that the supercurrent is largely carried by surface states, due to the inherent topology of the bands, and that it is robust against disorder. Our results thus clarify key open issues regarding the nature of supercurrents in topological insulators.

AB - Coupling the surface state of a topological insulator to an s-wave superconductor is predicted to produce the long-sought Majorana quasiparticle excitations. However, superconductivity has not been measured in surface states when the bulk charge carriers are fully depleted, that is, in the true topological regime relevant for investigating Majorana modes. Here we report measurements of d.c. Josephson effects in topological insulator-superconductor junctions as the chemical potential is moved through the true topological regime characterized by the presence of only surface currents. We compare our results with three-dimensional quantum transport simulations, and determine the effects of bulk/surface mixing, disorder and magnetic field; in particular, we show that the supercurrent is largely carried by surface states, due to the inherent topology of the bands, and that it is robust against disorder. Our results thus clarify key open issues regarding the nature of supercurrents in topological insulators.

UR - http://www.scopus.com/inward/record.url?scp=84877740685&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84877740685&partnerID=8YFLogxK

U2 - 10.1038/ncomms2701

DO - 10.1038/ncomms2701

M3 - Article

C2 - 23575693

AN - SCOPUS:84877740685

VL - 4

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

M1 - 1689

ER -