Connecting Higher-Order Topology with the Orbital Hall Effect in Monolayers of Transition Metal Dichalcogenides

Autor(es)

Costa, Marcio ; Focassio, Bruno ; Canonico, Luis M. ; Cysne, Tarik P. ; Schleder, Gabriel R. ; Muniz, R. B. ; Fazzio, Adalberto ; Rappoport, Tatiana G.

• Tipo de documento: Artigo Científico
• Fonte: Physical Review Letters; v. 130, n. 11, p. 7-pg., 2023-03-17.

Resumo

Monolayers of transition metal dichalcogenides (TMDs) in the 2H structural phase have been recently classified as higher-order topological insulators (HOTIs), protected by C-3 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 Z(4) 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. (AU)

• Processo FAPESP: 19/04527-0 - Interface entre isolantes topológicos cristalinos e materiais 2D-trivial: estudo de proximidade via defeitos
• Beneficiário: Bruno Focassio
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 17/02317-2 - Interfaces em materiais: propriedades eletrônicas, magnéticas, estruturais e de transporte
• Beneficiário: Adalberto Fazzio
• Modalidade de apoio: Auxílio à Pesquisa - Temático