Influence of spin-phonon coupling on antiferromagnetic spin fluctuations in FeSe under pressure: First-principles calculations with van der Waals corrections

The electronic structures, lattice dynamics, and magnetic properties of crystal beta -FeSe under hydrostatic pressure have been studied by using the first-principles electronic structure calculations with van der Waals corrections. With applied pressure, the energy bands around the Fermi energy leve...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2013-11, Vol.88 (20), Article 205130
Main Authors: Ye, Qian-Qian, Liu, Kai, Lu, Zhong-Yi
Format: Article
Language:English
Subjects:
Electronic structure
Fermi surfaces
Fluctuation
Iron
Joining
Mathematical analysis
Phonons
Superconductivity
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Summary:The electronic structures, lattice dynamics, and magnetic properties of crystal beta -FeSe under hydrostatic pressure have been studied by using the first-principles electronic structure calculations with van der Waals corrections. With applied pressure, the energy bands around the Fermi energy level consisting mainly of Fe-3d orbitals show obvious energy shifts and occupation variations, and meanwhile the frequencies of all optical phonon modes increase. Among these phonon modes, the A sub(1)g mode, which relates to the Se height from the Fe-Fe plane, shows a clear frequency jump in a pressure range between 5 and 6 GPa. This is also the pressure range within which the highest superconducting transition temperature T sub(c) of FeSe is reached in experiments. In comparison with other phonon modes, the atomic displacement due to the zero-point vibration of the A sub(1)g mode induces the strongest fluctuation of local magnetic moment on Fe under pressures from 0 to 9 GPa, and the induced fluctuation reaches a maximum around 5 GPa. These results suggest that the effect of phonon via spin-phonon coupling could not be completely omitted when exploring the superconducting mechanism in iron-based superconductors.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.88.205130