The low-energy ARPES and heat capacity of Na$_{0.3}$CoO$_2$: A DMFT study

TL;DR

This study uses dynamical mean-field theory (DMFT) to analyze the low-energy electronic structure and heat capacity of Na$_{0.3}$CoO$_2$, aiming to explain experimental observations in the Na-poor region of cobaltates.

Contribution

The paper applies DMFT to provide a quantitative explanation of ARPES and heat capacity data for Na$_{0.3}$CoO$_2$, highlighting the material's Fermi-liquid behavior.

Findings

Low-energy ARPES spectra consistent with Fermi-liquid theory

Heat capacity calculations match experimental values

Na$_{0.3}$CoO$_2$ exhibits weak correlations

Abstract

The cobaltates have demonstrated a wide variety complex behavior. The Na rich region of the phase diagram displays various degrees of anomalous behavior, such as Curie-Weiss behavior near a band insulator\cite{Foo:2004}, charge disproportionation\cite{Mukhamedshin:2005}, and non-Fermi-liquid behavior in the resistivity\cite{Foo:2004}. Alternatively, the Na poor region of the phase diagram appears to be a Fermi-liquid. The magnetic susceptibility displays Pauli behavior, the resistivity is roughly quadratic at low temperatures\cite{Foo:2004}, and the system appears to be homogeneous\cite{Mukhamedshin:2005}. Therefore, the Na poor region of the phase diagram seems like a natural starting point to attempt to explain the ARPES experiments and heat capacity measurements from a quantitative standpoint.