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

TL;DR

This study uses LDA+DMFT calculations to show that LaFeAsO exhibits a linear temperature dependence of magnetic susceptibility in the paramagnetic phase, aligning with experimental observations.

Contribution

The paper demonstrates that the linear-temperature dependence of magnetic susceptibility in LaFeAsO can be explained without antiferromagnetic fluctuations, highlighting orbital-dependent effects.

Findings

Magnetic susceptibility shows linear dependence at intermediate temperatures.

Susceptibility saturates and decreases at temperatures above 1000 K.

Orbital contributions significantly influence temperature dependence.

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.