Magnetically Induced Polarization in Centrosymmetric Bonds.
Phys Rev Lett
; 127(18): 187601, 2021 Oct 29.
Article
em En
| MEDLINE
| ID: mdl-34767415
ABSTRACT
We reveal the microscopic origin of electric polarization P[over â] induced by noncollinear magnetic order. We show that in Mott insulators, such P[over â] is given by all possible combinations of position operators r[over â][over ^]_{ij}=(r[over â]_{ij}^{0},r[over â]_{ij}) and transfer integrals t[over ^]_{ij}=(t_{ij}^{0},t_{ij}) in the bonds, where r[over â]_{ij}^{0} and t_{ij}^{0} are spin-independent contributions in the basis of Kramers doublet states, while r[over â]_{ij} and t_{ij} stem solely from the spin-orbit interaction. Among them, the combination t_{ij}^{0}r[over â]_{ij}, which couples to the spin current, remains finite in the centrosymmetric bonds, thus yielding finite P[over â] in the case of noncollinear arrangement of spins. The form of the magnetoelectric coupling, which is controlled by r[over â]_{ij}, appears to be rich and is not limited to the phenomenological law P[over â]â¼Îµ_{ij}×[e_{i}×e_{j}] with ε_{ij} being the bond vector connecting the spins e_{i} and e_{j}. Using density-functional theory, we illustrate how the proposed mechanism works in the spiral magnets CuCl_{2}, CuBr_{2}, CuO, and α-Li_{2}IrO_{3}, providing a consistent explanation for the available experimental data.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Qualitative_research
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article