Dynamic correlation suppresses antiferromagnetism in heavily doped Fe-pnictide superconductor LaFeAsO_1−xF_x

TY - JOUR

T1 - Dynamic correlation suppresses antiferromagnetism in heavily doped Fe-pnictide superconductor LaFeAsO1−xFx

AU - Banerjee, Hrishit

N1 - Copyright: © 2026 The Author(s). Published by the Royal Society of Chemistry.

PY - 2026/7/7

Y1 - 2026/7/7

N2 - LaFeAsO is a prototypical iron pnictide that exhibits stripe antiferromagnetism in its parent form and evolves into an unconventional superconductor upon fluorine doping, with transition temperatures reaching ∼41 K. The microscopic origin of the suppression of antiferromagnetism with doping, however, remains under debate, with chemical pressure effects often invoked as the primary mechanism. Here, we revisit this problem using a combination of density functional theory (DFT), DFT+U, hybrid functional approaches, and ab initio dynamical mean-field theory (DFT+DMFT). Taking LaFeAsO1−xFx at x = 0.5 as a representative heavily doped case, we demonstrate that chemical pressure alone is insufficient to fully suppress the antiferromagnetic state within static mean-field descriptions. In contrast, DFT+DMFT calculations reveal a collapse of long-range antiferromagnetic order at ∼58 K, just above the superconducting transition temperature, while the undoped compound retains robust magnetic order. This suppression is accompanied by a pronounced sharpening of the quasiparticle peak and a reduction in incoherent scattering, indicative of enhanced electronic coherence upon doping. Our results highlight the essential role of dynamic correlation effects, beyond one-electron and static mean-field approximations, in driving the suppression of magnetism in fluorine-doped LaFeAsO.

AB - LaFeAsO is a prototypical iron pnictide that exhibits stripe antiferromagnetism in its parent form and evolves into an unconventional superconductor upon fluorine doping, with transition temperatures reaching ∼41 K. The microscopic origin of the suppression of antiferromagnetism with doping, however, remains under debate, with chemical pressure effects often invoked as the primary mechanism. Here, we revisit this problem using a combination of density functional theory (DFT), DFT+U, hybrid functional approaches, and ab initio dynamical mean-field theory (DFT+DMFT). Taking LaFeAsO1−xFx at x = 0.5 as a representative heavily doped case, we demonstrate that chemical pressure alone is insufficient to fully suppress the antiferromagnetic state within static mean-field descriptions. In contrast, DFT+DMFT calculations reveal a collapse of long-range antiferromagnetic order at ∼58 K, just above the superconducting transition temperature, while the undoped compound retains robust magnetic order. This suppression is accompanied by a pronounced sharpening of the quasiparticle peak and a reduction in incoherent scattering, indicative of enhanced electronic coherence upon doping. Our results highlight the essential role of dynamic correlation effects, beyond one-electron and static mean-field approximations, in driving the suppression of magnetism in fluorine-doped LaFeAsO.

UR - https://www.scopus.com/pages/publications/105041972826

U2 - 10.1039/d6cc02568d

DO - 10.1039/d6cc02568d

M3 - Article

C2 - 42304785

AN - SCOPUS:105041972826

SN - 1359-7345

VL - 62

SP - 13110

EP - 13114

JO - Chemical Communications

JF - Chemical Communications

IS - 52

ER -