Research Highlights

Topological Breakthroughs: Tuning Quantum States in 2D Heterostructures

July 23, 2024

enlarge

Charge transfer at the interface between BiSe and Bi₂Se₃ induces giant Rashba splitting in a few layers of Bi₂Se₃.

Scientific Achievement

Through first principles calculations, CFN staff & collaborators engineered topological properties in 2D Bi₂Se₃/BiSe/transition metal dichalcogenide heterostructures through interface charge transfer, which creates Dirac surface electronic states.

Significance and Impact

This work presents a new method to control topological properties in 2D materials, with promise for designing better optimized electronic materials for quantum devices.

Research Details

Heterostructures of the topological insulator Bi₂Se₃ on transition metal dichalcogenides (TMDCs) offer a new materials platform for studying novel quantum states by exploiting the interplay among topological orders, charge orders, and magnetic orders. The diverse interface attributes, such as the material combination, charge rearrangement, defects, and strain, can be utilized to manipulate the quantum properties of this class of materials. Recent experiments with Bi₂Se₃/NbSe₂ heterostructures show signatures of strong Rashba band splitting due to the presence of a BiSe buffer layer, but the atomic level mechanism is not fully understood. We conduct first-principles studies of the Bi₂Se₃/BiSe/TMDC heterostructures with five different TMDC substrates (1T phase VSe₂, MoSe₂, and TiSe₂ and 2H phase NbSe₂ and MoSe₂). We find significant charge transfer at both BiSe/TMDC and Bi₂Se₃/BiSe interfaces driven by the work function difference, which stabilizes the BiSe layer as an electron donor. The electric field of the Bi₂Se₃/BiSe interface dipole breaks the inversion symmetry in the Bi₂Se₃ layer, leading to the giant Rashba band splitting in two quintuple layers and the recovery of the Dirac point in three quintuple layers, with the latter otherwise occurring only in thicker samples with at least six Bi₂Se₃ quintuple layers. In addition, we find that strain can significantly affect the charge transfer at the interfaces. Our study presents a promising avenue for tuning topological properties in heterostructures of two-dimensional materials, with potential applications in quantum devices.

• The interface dipole field in the 2D heterostructure breaks inversion symmetry, leading to a giant Rashba band splitting and reemergence of Dirac surface states in thin Bi₂Se₃
• The study further highlights the role of strain on charge transfer and topological properties.

Publication Reference

Jiang, Xuance, Turgut Yilmaz, Elio Vescovo, and Deyu Lu. "Manipulating topological properties in Bi 2 Se 3/BiSe/transition metal dichalcogenide heterostructures with interface charge transfer." Physical Review B 109, 115112 (2024).

DOI: https://doi.org/10.1103/PhysRevB.109.115112
OSTI: www.osti.gov/biblio/2338135

Acknowledgment of Support

We thank Dr. C.-Z. Chang for providing the ARPES data used in this study. We thank Dr. J. Cano for the valuable discussions. This research used the Theory and Computation resources from the Center for Functional Nanomaterials (CFN) and resources of the National Synchrotron Light Source II, which are U.S. Department of Energy Office of Science User Facilities, operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.

2024-22059  |  INT/EXT  |  Newsroom