Optical properties of TlNi2Se2: Observation of pseudogap formation

Abstract

The quasi-two-dimensional nickel chalcogenides $TlN{i}_{2}S{e}_2$ is a newly discovered superconductor. We have performed optical spectroscopy study on $TlN{i}_{2}S{e}_2$ single crystals over a broad frequency range at various temperatures. The overall optical reflectance spectra are similar to those observed in its isostructure $BaN{i}_{2}A{s}_2$. Both the suppression in $R(\omega )$ and the peaklike feature in ${\sigma }_1(\omega )$ suggest the progressive formation of a pseudogap feature in the midinfrared range with decreasing temperatures, which might be originated from the dynamic local fluctuation of charge-density-wave (CDW) instability. We propose that the CDW instability in $TlN{i}_{2}S{e}_2$ is driven by the saddle points mechanism, due to the existence of van Hove singularity very close to the Fermi energy.

5 pages, 4 figures

References in corpus (13)

• Origin of the spin density wave instability in AFe${}_2$As${}_2$ (A=Ba, Sr) as revealed by optical spectroscopy
• First Order Phase Transition and Superconductivity in BaNi2As2 Single Crystals
• Use of X-ray scattering functions in Kramers-Kronig analysis of reflectance
• Strong-coupling superconductivity in layered nickel-based LaO${}_{1-x}$F${}_x$NiAs
• Density functional study of BaNi${}_2$As${}_2$: Electronic structure, phonons and electron-phonon superconductivity
• Mixed-Valence-Driven Heavy-Fermion Behavior and Superconductivity in KNi${}_2$Se${}_2$
• Optical study of the charge-density-wave mechanism in 2$H$-TaS${}_2$ and Na${}_x$TaS${}_2$
• Electronic band structure of BaCo${}_2$As${}_2$: a fully-doped ferropnictide with reduced electronic correlations
• Electronic structure of BaNi${}_2$As${}_2$
• Multi-gap nodeless superconductivity in nickel chalcogenide TlNi2Se2
• Camelback-shaped band reconciles heavy electron behavior with weak electronic Coulomb correlations in superconducting TlNi2Se2
• Theory of Charge Order and Heavy-Electron Formation in the Mixed-Valence Compound KNi${}_2$Se${}_2$
• The weak electronic correlations and absence of heavy Fermion state in KNi${}_2$Se${}_2$

Cited by in corpus (1)

• Unconventional superconductivity in the nickel-chalcogenide superconductor, TlNi${}_2$Se${}_2$