Linear-Temperature Dependence of Static Magnetic Susceptibility in LaFeAsO from Dynamical Mean-Field Theory

Abstract

In this Letter we report the LDA+DMFT (method combining Local Density Approximation with Dynamical Mean-Field Theory) results for magnetic properties of parent superconductor LaFeAsO in paramagnetic phase. Calculated uniform magnetic susceptibility shows linear dependence at intermediate temperatures in agreement with experimental data. For high temperatures ($>$1000 K) calculations show saturation and then susceptibility decreases with temperature. Contributions to temperature dependence of the uniform susceptibility are strongly orbitally dependent. It is related to the form of the orbitally-resolved spectral functions near the Fermi energy with strong temperature dependent narrow peaks for some of the orbitals. Our results demonstrate that linear-temperature dependence of static magnetic susceptibility in pnictide superconductors can be reproduced without invoking antiferromagnetic fluctuations.