Campus Units

Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

7-1-2011

Journal or Book Title

Physical Review B

Volume

84

Issue

2

First Page

020509(R)

DOI

10.1103/PhysRevB.84.020509

Abstract

We used angle-resolved photoemission spectroscopy and thermoelectric power to study the poorly explored, highly overdoped side of the phase diagram of Ba(Fe1−xCox)2As2 high-temperature superconductor. Our data demonstrate that several Lifshitz transitions—topological changes of the Fermi surface—occur for large x. The central hole barrel changes to ellipsoids that are centered at Z at x∼0.11 and subsequently disappear around x∼0.2; changes in thermoelectric power occur at similar x values. Tc decreases and goes to zero around x∼0.15—between the two Lifshitz transitions. Beyond x=0.2 the central pocket becomes electron-like and superconductivity does not exist. Our observations reveal the importance of the underlying Fermiology in electron-doped iron arsenides. We speculate that a likely necessary condition for superconductivity in these materials is the presence of the central hole pockets rather than nesting between central and corner pockets.

Comments

This article is published as Liu, Chang, A. D. Palczewski, R. S. Dhaka, Takeshi Kondo, R. M. Fernandes, E. D. Mun, H. Hodovanets, A. N. Thaler, J. Schmalian, S. L. Bud’ko, P. C. Canfield, and A. Kaminski. "Importance of the Fermi-surface topology to the superconducting state of the electron-doped pnictide Ba (Fe 1− x Co x) 2 As 2." Physical Review B 84, no. 2 (2011): 020509. DOI: 10.1103/PhysRevB.84.020509. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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