RESUMO
The two-dimensional (2D) honeycomb lattice has attracted intensive research interest due to the appearance of Dirac-type band structures as the consequence of two sublattices in the honeycomb structure. Introducing strong spin-orbit coupling (SOC) leads to a gap opening at the Dirac point, transforming the honeycomb lattice into a 2D topological insulator as a platform for the quantum spin Hall effect (QSHE). In this work, we realize a 2D honeycomb-structured film with tellurium, the heaviest nonradioactive element in Group VI, namely, tellurene, via molecular beam epitaxy. We revealed the gap opening of 160 meV at the Dirac point due to the strong SOC in the honeycomb-structured tellurene by angle-resolved photoemission spectroscopy. The topological edge states of tellurene are detected via scanning tunneling microscopy/spectroscopy. These results demonstrate that tellurene is a novel 2D honeycomb lattice with strong SOC, and they unambiguously prove that tellurene is a promising candidate for a room-temperature QSHE system.
RESUMO
Topological materials have broad application prospects in quantum computing and spintronic devices. Among them, dual topological materials with low dimensionality provide an excellent platform for manipulating various topological states and generating highly conductive spin currents. However, direct observation of their topological surface states still lacks. Here, we reveal the coexistence of the strong and weak topological phases in a quasi-one-dimensional material, TaNiTe_{5}, by spin- and angle- resolved photoemission spectroscopy. The surface states protected by weak topological order forms Dirac-node arcs in the vicinity of the Fermi energy, providing the opportunity to develop spintronics devices with high carrier density that is tunable by bias voltage.
