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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. Radović, Hangdong Wang, Qianhui Mao, Jianhua Du, Minghu Fang, J. Mesot, H. Ding, M. Shi

DOI 10.1103/PhysRevB.92.081116 · Physical Review B

T1

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Abstract

Combining photoemission spectroscopy, Raman spectroscopy, and first-principles calculations, we characterize superconducting TlNi2Se2 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 TlNi2Se2 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 Sommerfeld coefficient [H. Wang et al., Phys. Rev. Lett 111, 207001 (2013)] in this weakly correlated compound.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
TlNi2Se2

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Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

3.7Pressure not reportedunknown
KNi2Se2

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Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

0.8Pressure not reportedunknown

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