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arXiv · 1412.7016

Camelback-shaped band reconciles heavy electron behavior with weak electronic Coulomb correlations in superconducting TlNi2Se2

N. Xu·C. E. Matt·P. Richard·A. van Roekeghem·S. Biermann·X. Shi·S. -F. Wu·H. W. Liu·D. Chen·T. Qian·N. C. Plumb·M. Radovic·Hangdong Wang·Qianhui Mao·Jianhua Du·Minghu Fang·J. Mesot·H. Ding·M. Shi
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Abstract

Using high-resolution photoemission spectroscopy and first-principles calculations, we characterize superconducting TlNi$_2$Se$_2$ as a material with weak electronic Coulomb correlations leading to a bandwidth renormalization of 1.4. We identify a camelback-shaped band, whose energetic position strongly depends on the selenium height. While this feature is universal in transition metal pnictides, in TlNi$_2$Se$_2$ it lies in the immediate vicinity of the Fermi level, giving rise to a pronounced van Hove singularity. The resulting heavy band mass resolves the apparent puzzle of a large normal-state specific heat coefficient (Phys. Rev. Lett. 112, 207001) in this weakly correlated compound.

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N. Xu, C. E. Matt, P. Richard, A. van Roekeghem, S. Biermann, X. Shi, S. -F. Wu, H. W. Liu, D. Chen, T. Qian, N. C. Plumb, M. Radovic, Hangdong Wang, Qianhui Mao, Jianhua Du, Minghu Fang, J. Mesot, H. Ding, M. Shi. 2014-12-22. Camelback-shaped band reconciles heavy electron behavior with weak electronic Coulomb correlations in superconducting TlNi2Se2. https://doi.org/10.1103/physrevb.92.081116

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