Photoemission Spectral Weight Transfer and Mass Renormalization in the Fermi-Liquid System La$_{1-x}$Sr$_x$TiO$_{3+y/2}$

TL;DR

This study investigates how spectral weight transfer and mass renormalization evolve with hole doping in La$_{1-x}$Sr$_x$TiO$_{3+y/2}$ near the metal-insulator transition, revealing band narrowing and spectral weight redistribution.

Contribution

It provides new insights into the relationship between spectral weight transfer, mass renormalization, and magnetic ordering in a Fermi-liquid system near the MIT.

Findings

Mass renormalization aligns with specific heat data.

Band narrowing is prominent near the chemical potential.

Spectral weight shifts from coherent to incoherent parts during antiferromagnetic ordering.

Abstract

We have performed a photoemission study of La$_{1-x}$Sr$_x$TiO$_{3+y/2}$ near the filling-control metal-insulator transition (MIT) as a function of hole doping. Mass renormalization deduced from the spectral weight and the width of the quasi-particle band around the chemical potential $\mu$ is compared with that deduced from the electronic specific heat. The result implies that, near the MIT, band narrowing occurs strongly in the vicinity of $\mu$. Spectral weight transfer occurs from the coherent to the incoherent parts upon antiferromagnetic ordering, which we associate with the partial gap opening at $\mu$.