$\text{LDA}+\text{DMFT}$ spectral functions and effective electron mass enhancement in the superconductor LaFePO

$LDA + DMFT$ spectral functions and effective electron mass enhancement in the superconductor LaFePO

S. L. Skornyakov, N. A. Skorikov, A. V. Lukoyanov, A. O. Shorikov, and V. I. Anisimov

Phys. Rev. B 81, 174522 – Published 21 May 2010

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 [D. H. Lu et al., Nature (London) 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 et al., Nat. Phys. 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.