Connecting higher-order topology with the orbital hall effect in monolayers of transition metal dichalcogenides
Costa, Marcio (Universidade Federal Fluminense. Instituto de Física)
Focassio, Bruno (Universidade Federal do ABC (Brasil))
Canonico, Luis M. (Institut Català de Nanociència i Nanotecnologia)
Cysne, Tarik P (Universidade Federal Fluminense. Instituto de Física)
Schleder, Gabriel R. (Harvard University. John A. Paulson School of Engineering and Applied Sciences)
Muniz, R. B. (Universidade Federal Fluminense. Instituto de Física)
Fazzio, Adalberto (Centro Nacional de Pesquisa em Energia e Materiais. Ilum Escola de Ciência)
Rappoport, Tatiana Gabriela (Universidade de Lisboa. Instituto de Telecomunicações)

Data:	2023
Resum:	Monolayers of transition metal dichalcogenides (TMDs) in the 2H structural phase have been recently classified as higher-order topological insulators (HOTIs), protected by C3 rotation symmetry. In addition, theoretical calculations show an orbital Hall plateau in the insulating gap of TMDs, characterized by an orbital Chern number. We explore the correlation between these two phenomena in TMD monolayers in two structural phases: the noncentrosymmetric 2H and the centrosymmetric 1T. Using density functional theory, we confirm the characteristics of 2H TMDs and reveal that 1T TMDs are identified by a Z4 topological invariant. As a result, when cut along appropriate directions, they host conducting edge states, which cross their bulk energy-band gaps and can transport orbital angular momentum. Our linear response calculations thus indicate that the HOTI phase is accompanied by an orbital Hall effect. Using general symmetry arguments, we establish a connection between the two phenomena with potential implications for orbitronics and spin orbitronics.
Ajuts:	Agencia Estatal de Investigación PID2019-106684GB-I00 Agencia Estatal de Investigación SEV-2017-0706
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Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Classifieds ; Dichalcogenides ; High-order ; Higher-order ; Orbitals ; Orbitronics ; Order topologies ; Rotation symmetry ; Structural phasis ; Topological insulators
Publicat a:	Physical review letters, Vol. 130, issue 11 (March 2023) , art. 116204, ISSN 1079-7114

DOI: 10.1103/PhysRevLett.130.116204

Postprint 20 p, 7.1 MB

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