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

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.

5 pages, 4 figures

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Cited by in corpus (6)

• Spectral properties of transition metal pnictides and chalcogenides: angle-resolved photoemission spectroscopy and dynamical mean field theory
• Superconductivity in a new layered nickel-selenide CsNi2Se2
• Angle-resolved spectroscopy study of Ni-based superconductor SrNi${}_2$As${}_2$
• Optical properties of TlNi2Se2: Observation of pseudogap formation
• Single crystal growth and superconductivity in RbNi${}_2$Se${}_2$
• Unconventional superconductivity in the nickel-chalcogenide superconductor, TlNi${}_2$Se${}_2$