We perform density-functional calculations of the magnetic properties of a simplified structure aimed at capturing some of the features of the elusive epsilon phase of molecular oxygen at high pressure. Starting with the delta phase-which is a quasi-two-dimensional distorted triangular arrangement of antiferromagnetically ordered molecules-pressure could decrease the bla ratio in the basal planes pushing it toward the ideal triangular value of 1/root 3, thus increasing magnetic frustration. We conjecture that when frustration takes over, the magnetic order may turn into a 120 degrees planar spin-spiral structure inside the epsilon phase, until at higher pressures hand-overlap metallization suppresses magnetization in the zeta phase. This conjecture is substantiated by calculations that also represent the attempt to apply state-of-the-art pseudopotential techniques to the magnetic properties of a frustrated antiferromagnet.

Noncolinear spin polarization from frustrated antiferromagnetism: A possible scenario for molecular oxygen at high pressure / Gebauer, R.; Serra, S.; Chiarotti, G. L.; Scandolo, S.; Baroni, S.; Tosatti, E.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 61:9(2000), pp. 6145-6149. [10.1103/PhysRevB.61.6145]

Noncolinear spin polarization from frustrated antiferromagnetism: A possible scenario for molecular oxygen at high pressure

Scandolo, S.;Baroni, S.;Tosatti, E.
2000-01-01

Abstract

We perform density-functional calculations of the magnetic properties of a simplified structure aimed at capturing some of the features of the elusive epsilon phase of molecular oxygen at high pressure. Starting with the delta phase-which is a quasi-two-dimensional distorted triangular arrangement of antiferromagnetically ordered molecules-pressure could decrease the bla ratio in the basal planes pushing it toward the ideal triangular value of 1/root 3, thus increasing magnetic frustration. We conjecture that when frustration takes over, the magnetic order may turn into a 120 degrees planar spin-spiral structure inside the epsilon phase, until at higher pressures hand-overlap metallization suppresses magnetization in the zeta phase. This conjecture is substantiated by calculations that also represent the attempt to apply state-of-the-art pseudopotential techniques to the magnetic properties of a frustrated antiferromagnet.
2000
61
9
6145
6149
Gebauer, R.; Serra, S.; Chiarotti, G. L.; Scandolo, S.; Baroni, S.; Tosatti, E.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/13893
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