Perfect Andreev reflection due to the Klein paradox in a topological superconducting state

Seunghun Lee, Valentin Stanev, Xiaohang Zhang, Drew Stasak, Jack Flowers, Joshua S. Higgins, Sheng Dai, Thomas Blum, Xiaoqing Pan, Victor Yakovenko, Johnpierre Paglione, Richard L. Greene, Victor Galitski and Ichiro Takeuchi ()
Additional contact information
Seunghun Lee: University of Maryland
Valentin Stanev: University of Maryland
Xiaohang Zhang: University of Maryland
Drew Stasak: University of Maryland
Jack Flowers: University of Maryland
Joshua S. Higgins: University of Maryland
Sheng Dai: University of California
Thomas Blum: University of California
Xiaoqing Pan: University of California
Johnpierre Paglione: University of Maryland
Richard L. Greene: University of Maryland
Victor Galitski: University of Maryland
Ichiro Takeuchi: University of Maryland

Nature, 2019, vol. 570, issue 7761, 344-348

Abstract: Abstract In 1928, Dirac proposed a wave equation to describe relativistic electrons1. Shortly afterwards, Klein solved a simple potential step problem for the Dirac equation and encountered an apparent paradox: the potential barrier becomes transparent when its height is larger than the electron energy. For massless particles, backscattering is completely forbidden in Klein tunnelling, leading to perfect transmission through any potential barrier2,3. The recent advent of condensed-matter systems with Dirac-like excitations, such as graphene and topological insulators, has opened up the possibility of observing Klein tunnelling experimentally4–6. In the surface states of topological insulators, fermions are bound by spin–momentum locking and are thus immune from backscattering, which is prohibited by time-reversal symmetry. Here we report the observation of perfect Andreev reflection in point-contact spectroscopy—a clear signature of Klein tunnelling and a manifestation of the underlying ‘relativistic’ physics of a proximity-induced superconducting state in a topological Kondo insulator. Our findings shed light on a previously overlooked aspect of topological superconductivity and can serve as the basis for a unique family of spintronic and superconducting devices, the interface transport phenomena of which are completely governed by their helical topological states.

Date: 2019
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/s41586-019-1305-1 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:570:y:2019:i:7761:d:10.1038_s41586-019-1305-1

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-019-1305-1

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().