Evidence for topologically protected surface states and a superconducting phase in [Tl4](Tl(1-x)Sn(x))Te3 using photoemission, specific heat, and magnetization measurements, and density functional theory

K E Arpino; D C Wallace; Y F Nie; T Birol; P D C King; S Chatterjee; M Uchida; S M Koohpayeh; J-J Wen; K Page; C J Fennie; K M Shen; T M McQueen

doi:10.1103/PhysRevLett.112.017002

Evidence for topologically protected surface states and a superconducting phase in [Tl4](Tl(1-x)Sn(x))Te3 using photoemission, specific heat, and magnetization measurements, and density functional theory

Phys Rev Lett. 2014 Jan 10;112(1):017002. doi: 10.1103/PhysRevLett.112.017002. Epub 2014 Jan 8.

Authors

K E Arpino¹, D C Wallace¹, Y F Nie², T Birol³, P D C King⁴, S Chatterjee⁵, M Uchida⁵, S M Koohpayeh⁶, J-J Wen⁶, K Page⁷, C J Fennie³, K M Shen⁴, T M McQueen¹

Affiliations

¹ Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA and Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
² Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA and Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
³ School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
⁴ Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA and Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA.
⁵ Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
⁶ Institute for Quantum Matter, Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
⁷ Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.

PMID: 24483920
DOI: 10.1103/PhysRevLett.112.017002

Abstract

We report the discovery of surface states in the perovskite superconductor [Tl4]TlTe3 (Tl5Te3) and its nonsuperconducting tin-doped derivative [Tl4](Tl0.4Sn0.6)Te3 as observed by angle-resolved photoemission spectroscopy. Density functional theory calculations predict that the surface states are protected by a Z2 topology of the bulk band structure. Specific heat and magnetization measurements show that Tl5Te3 has a superconducting volume fraction in excess of 95%. Thus Tl5Te3 is an ideal material in which to study the interplay of bulk band topology and superconductivity.