LDA+DMFT Spectral Functions and Effective Electron Mass Enhancement in Superconductor LaFePO

TL;DR

This paper uses LDA+DMFT to analyze spectral functions and electron mass enhancement in LaFePO, showing moderate correlations that are common across Fe-based superconductors, but not directly linked to transition temperatures.

Contribution

First LDA+DMFT study of LaFePO spectral properties, aligning theoretical results with experimental data and highlighting the role of moderate electronic correlations.

Findings

Spectral functions match ARPES data

Effective mass enhancement m*/m ≈ 1.9–2.2

Correlations are similar across Fe-based superconductors

Abstract

In this Letter we report the first LDA+DMFT results (method combining Local Density Approximation with Dynamical Mean-Field Theory) for spectral properties of superconductor LaFePO. Calculated {\bf k}-resolved spectral functions reproduce recent angle-resolved photoemission spectroscopy (ARPES) data [D. H. Lu {\it et al}., Nature {\bf 455}, 81 (2008)]. Obtained effective electron mass enhancement values $m^{*}/m\approx$ 1.9 -- 2.2 are in good agreement with infrared and optical studies [M. M. Qazilbash {\it et al}., Nature Phys. {\bf 5}, 647 (2009)], de Haas--van Alphen, electrical resistivity, and electronic specific heat measurements results, that unambiguously evidence for moderate correlations strength in LaFePO. Similar values of $m^{*}/m$ were found in the other Fe-based superconductors with substantially different superconducting transition temperatures. Thus, the dynamical correlation effects are essential in the Fe-based superconductors, but the strength of electronic correlations does not determine the value of superconducting transition temperature.