Topologically protected surface states in a centrosymmetric superconductor β-PdBi2

The topological aspects of electrons in solids can emerge in real materials, as represented by topological insulators. In theory, they show a variety of new magneto-electric phenomena, and especially the ones hosting superconductivity are strongly desired as candidates for topological superconductor...

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Main Authors:	Sakano, M., Okawa, K., Kanou, M., Sanjo, H., Okuda, T., Sasagawa, T., Ishizaka, K
Format:	Online
Language:	English
Published:	Nature Pub. Group 2015
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633943/

id	pubmed-4633943
recordtype	oai_dc
spelling	pubmed-46339432015-11-25 Topologically protected surface states in a centrosymmetric superconductor β-PdBi2 Sakano, M. Okawa, K. Kanou, M. Sanjo, H. Okuda, T. Sasagawa, T. Ishizaka, K Article The topological aspects of electrons in solids can emerge in real materials, as represented by topological insulators. In theory, they show a variety of new magneto-electric phenomena, and especially the ones hosting superconductivity are strongly desired as candidates for topological superconductors. While efforts have been made to develop possible topological superconductors by introducing carriers into topological insulators, those exhibiting indisputable superconductivity free from inhomogeneity are very few. Here we report on the observation of topologically protected surface states in a centrosymmetric layered superconductor, β-PdBi2, by utilizing spin- and angle-resolved photoemission spectroscopy. Besides the bulk bands, several surface bands are clearly observed with symmetrically allowed in-plane spin polarizations, some of which crossing the Fermi level. These surface states are precisely evaluated to be topological, based on the Z2 invariant analysis in analogy to three-dimensional strong topological insulators. β-PdBi2 may offer a solid stage to investigate the topological aspect in the superconducting condensate. Nature Pub. Group 2015-10-13 /pmc/articles/PMC4633943/ /pubmed/26460338 http://dx.doi.org/10.1038/ncomms9595 Text en Copyright © 2015, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved. http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Sakano, M. Okawa, K. Kanou, M. Sanjo, H. Okuda, T. Sasagawa, T. Ishizaka, K
spellingShingle	Sakano, M. Okawa, K. Kanou, M. Sanjo, H. Okuda, T. Sasagawa, T. Ishizaka, K Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
author_facet	Sakano, M. Okawa, K. Kanou, M. Sanjo, H. Okuda, T. Sasagawa, T. Ishizaka, K
author_sort	Sakano, M.
title	Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
title_short	Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
title_full	Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
title_fullStr	Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
title_full_unstemmed	Topologically protected surface states in a centrosymmetric superconductor β-PdBi2
title_sort	topologically protected surface states in a centrosymmetric superconductor β-pdbi2
description	The topological aspects of electrons in solids can emerge in real materials, as represented by topological insulators. In theory, they show a variety of new magneto-electric phenomena, and especially the ones hosting superconductivity are strongly desired as candidates for topological superconductors. While efforts have been made to develop possible topological superconductors by introducing carriers into topological insulators, those exhibiting indisputable superconductivity free from inhomogeneity are very few. Here we report on the observation of topologically protected surface states in a centrosymmetric layered superconductor, β-PdBi2, by utilizing spin- and angle-resolved photoemission spectroscopy. Besides the bulk bands, several surface bands are clearly observed with symmetrically allowed in-plane spin polarizations, some of which crossing the Fermi level. These surface states are precisely evaluated to be topological, based on the Z2 invariant analysis in analogy to three-dimensional strong topological insulators. β-PdBi2 may offer a solid stage to investigate the topological aspect in the superconducting condensate.
publisher	Nature Pub. Group
publishDate	2015
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633943/
_version_	1613497718952427520

Topologically protected surface states in a centrosymmetric superconductor β-PdBi2

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