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

Abstract

In this paper we report LDA+DMFT results (method combining local-density approximation with dynamical mean-field theory) for spectral properties of superconductor LaFePO. Calculated k -resolved spectral functions reproduce recent angle-resolved photoemission spectroscopy data. Obtained effective electron mass enhancement values m/≈1.9-2.2 are in good agreement with infrared and optical studies, 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. © 2010 The American Physical Society