Topologically Protected Surface States in a Centrosymmetric Superconductor β-PdBi2

Overview

Journal Nat Commun

Specialty Biology

Date 2015 Oct 14

PMID 26460338

Citations 13

Authors

M Sakano

K Okawa

M Kanou

H Sanjo

T Okuda

T Sasagawa

K Ishizaka

Affiliations

Soon will be listed here.

Abstract

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.

Citing Articles

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References

Okuda T, Miyamaoto K, Miyahara H, Kuroda K, Kimura A, Namatame H . Efficient spin resolved spectroscopy observation machine at Hiroshima Synchrotron Radiation Center. Rev Sci Instrum. 2011; 82(10):103302. DOI: 10.1063/1.3648102. View

Zhu J, Zhang J, Kong P, Zhang S, Yu X, Zhu J . Superconductivity in topological insulator Sb2Te3 induced by pressure. Sci Rep. 2013; 3:2016. PMC: 3687246. DOI: 10.1038/srep02016. View

Levy N, Zhang T, Ha J, Sharifi F, Talin A, Kuk Y . Experimental evidence for s-wave pairing symmetry in superconducting Cu(x)Bi2Se3 single crystals using a scanning tunneling microscope. Phys Rev Lett. 2014; 110(11):117001. DOI: 10.1103/PhysRevLett.110.117001. View

Perdew , Burke , Ernzerhof . Generalized Gradient Approximation Made Simple. Phys Rev Lett. 1996; 77(18):3865-3868. DOI: 10.1103/PhysRevLett.77.3865. View

Hosur P, Ghaemi P, Mong R, Vishwanath A . Majorana modes at the ends of superconductor vortices in doped topological insulators. Phys Rev Lett. 2011; 107(9):097001. DOI: 10.1103/PhysRevLett.107.097001. View

Sasaki S, Ren Z, Taskin A, Segawa K, Fu L, Ando Y . Odd-parity pairing and topological superconductivity in a strongly spin-orbit coupled semiconductor. Phys Rev Lett. 2012; 109(21):217004. DOI: 10.1103/PhysRevLett.109.217004. View

Liu Z, Jiang J, Zhou B, Wang Z, Zhang Y, Weng H . A stable three-dimensional topological Dirac semimetal Cd3As2. Nat Mater. 2014; 13(7):677-81. DOI: 10.1038/nmat3990. View

Fu L . Hexagonal warping effects in the surface states of the topological insulator Bi2Te3. Phys Rev Lett. 2010; 103(26):266801. DOI: 10.1103/PhysRevLett.103.266801. View

Fu L, Kane C . Superconducting proximity effect and majorana fermions at the surface of a topological insulator. Phys Rev Lett. 2008; 100(9):096407. DOI: 10.1103/PhysRevLett.100.096407. View

10.

Chen Y, Analytis J, Chu J, Liu Z, Mo S, Qi X . Experimental realization of a three-dimensional topological insulator, Bi2Te3. Science. 2009; 325(5937):178-81. DOI: 10.1126/science.1173034. View

11.

Zhang J, Zhang S, Weng H, Zhang W, Yang L, Liu Q . Pressure-induced superconductivity in topological parent compound Bi2Te3. Proc Natl Acad Sci U S A. 2010; 108(1):24-8. PMC: 3017179. DOI: 10.1073/pnas.1019040108. View

12.

Fu L, Berg E . Odd-parity topological superconductors: theory and application to CuxBi2Se3. Phys Rev Lett. 2010; 105(9):097001. DOI: 10.1103/PhysRevLett.105.097001. View

13.

Hsieh T, Fu L . Majorana fermions and exotic surface Andreev bound states in topological superconductors: application to Cu(x)Bi2Se3. Phys Rev Lett. 2012; 108(10):107005. DOI: 10.1103/PhysRevLett.108.107005. View

14.

Lin H, Wray L, Xia Y, Xu S, Jia S, Cava R . Half-Heusler ternary compounds as new multifunctional experimental platforms for topological quantum phenomena. Nat Mater. 2010; 9(7):546-9. DOI: 10.1038/nmat2771. View

15.

Sun Z, Enayat M, Maldonado A, Lithgow C, Yelland E, Peets D . Dirac surface states and nature of superconductivity in Noncentrosymmetric BiPd. Nat Commun. 2015; 6:6633. PMC: 4389226. DOI: 10.1038/ncomms7633. View

16.

Alicea J . New directions in the pursuit of Majorana fermions in solid state systems. Rep Prog Phys. 2012; 75(7):076501. DOI: 10.1088/0034-4885/75/7/076501. View

17.

Okazaki K, Ota Y, Kotani Y, Malaeb W, Ishida Y, Shimojima T . Octet-line node structure of superconducting order parameter in KFe2As2. Science. 2012; 337(6100):1314-7. DOI: 10.1126/science.1222793. View

18.

Hor Y, Williams A, Checkelsky J, Roushan P, Seo J, Xu Q . Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator. Phys Rev Lett. 2010; 104(5):057001. DOI: 10.1103/PhysRevLett.104.057001. View

19.

Kriener M, Segawa K, Ren Z, Sasaki S, Ando Y . Bulk superconducting phase with a full energy gap in the doped topological insulator Cu(x)Bi₂Se₃. Phys Rev Lett. 2011; 106(12):127004. DOI: 10.1103/PhysRevLett.106.127004. View

20.

Sasaki S, Kriener M, Segawa K, Yada K, Tanaka Y, Sato M . Topological Superconductivity in Cu(x)Bi(2)Se(3). Phys Rev Lett. 2011; 107(21):217001. DOI: 10.1103/PhysRevLett.107.217001. View