Electronic structure of La(2)CoSi(3) - a non-Kondo analogue of a Kondo lattice, Ce(2)CoSi(3)

TL;DR

This study investigates the electronic structure of La(2)CoSi(3), revealing significant electron correlations and complex temperature-dependent behaviors, providing insights into Kondo lattice systems and serving as a reference for Ce-based compounds.

Contribution

It offers the first detailed analysis of La(2)CoSi(3)'s electronic structure, highlighting correlation effects and temperature evolution relevant to Kondo lattice physics.

Findings

Electron correlation strength among Co 3d electrons is close to 3 eV.

Core level spectra show correlation-induced satellite features.

Temperature dependence reveals deviations from Fermi liquid behavior.

Abstract

We study the electronic structure of a Pauli paramagnetic compound, La(2)CoSi(3) using photoemission spectroscopy and ab initio band structure calculations. Experimental valence band spectra exhibit signature of electron correlation induced feature around 2.5 eV - the correlation strength among Co 3d electrons is estimated to be close to 3 eV. The Co 2p core level spectra also exhibit correlation induced satellite features consistent with the scenario in the valence band spectra suggesting importance of conduction electron correlation in addition to the local moment in Kondo lattice systems. The La(2)CoSi(3) valence band spectra could be utilized to extract Ce 4f related spectral features and thus provide a good reference to study Kondo lattice systems in this class of materials. Temperature evolution of various core level spectra is found to be complex revealing deviations from a typical Fermi liquid behavior and emergence of distinct surface-bulk difference in the electronic structure at finite temperature.