Microscopic origin of multiferroic order in monolayer NiI$_2$
| Autor: | Adolfo O Fumega, J L Lado |
|---|---|
| Přispěvatelé: | Correlated Quantum Materials (CQM), Department of Applied Physics, Aalto-yliopisto, Aalto University |
| Rok vydání: | 2021 |
| Předmět: |
Condensed Matter - Materials Science
Condensed Matter - Strongly Correlated Electrons Condensed Matter::Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Strongly Correlated Electrons (cond-mat.str-el) Mechanics of Materials Mechanical Engineering Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences General Materials Science General Chemistry Condensed Matter Physics |
| DOI: | 10.48550/arxiv.2111.07909 |
| Popis: | The discovery of multiferroic behavior in monolayer NiI$_2$ provides a new symmetry-broken state in van der Waals monolayers, featuring the simultaneous emergence of helimagnetic order and ferroelectric order at a critical temperature of $T=21$ K. However, the microscopic origin of multiferroic order in NiI$_2$ monolayer has not been established, and in particular, the role of non-colinear magnetism and spin-orbit coupling in this compound remains an open problem. Here we reveal the origin of the two-dimensional multiferroicity in NiI$_2$ using first-principles electronic structure methods. We show that the helimagnetic state appears as a consequence of the long-range magnetic exchange interactions, featuring sizable magnetic moments in the iodine atoms. We demonstrate that the electronic density reconstruction accounting for the ferroelectric order emerges from the interplay of non-collinear magnetism and spin-orbit coupling. We demonstrate that the ferroelectric order is controlled by the iodine spin-orbit coupling, and leads to an associated electronically-driven distortion in the lattice. Our results establish the microscopic origin of the multiferroic behavior in monolayer NiI$_2$, putting forward the coexistence of helical magnetic order and ligand spin-orbit coupling as driving forces for multiferroic behavior in two-dimensional materials. Comment: 7 pages, 4 figures |
| Databáze: | OpenAIRE |
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