Speaker
Description
Topological materials have been widely studied because of their novel properties that enable robust quantum transport phenomena along the edges and surfaces of the materials. These effects contribute to many possible technological developments, especially in quantum technology$^{1,2}$.
Bi$_2$Se$_3$, one of the most selected topological insulators that was discovered to have a three-dimensional structure, can maintain its topological properties under non-equilibrium conditions and up to room temperature due to its large insulating gap of about 300 meV$^3$ and can be developed to a promising quantum platform.
Normally, a qubit, the smallest unit of a quantum computer, is extremely sensitive to disturbances such as thermal and electromagnetic interactions. However, utilizing the hybridized topological surface states (TSSs) of a Bi$_2$Se$_3$ ultrathin film as a qubit could significantly enhance the durability of quantum nanodevices and information flow throughout quantum circuits against multiple perturbations$^2$.
In this work, the intrinsic properties of bulk Bi$_2$Se$_3$ are investigated using density functional theory (DFT), where the electronic structure is further interpolated using maximally localized Wannier functions (MLWFs). The resulting energy eigenvalues are projected onto Liu’s four-band low-energy model Hamiltonian$^{2,4}$ to extract the kinetic energy and spin–orbit coupling (SOC) terms. These parameters are then applied to surface structures to determine the spatial distributions of the electron wavefunctions using the finite difference method. Finally, qubit states are constructed on the top and bottom surfaces of the thin film through superpositions of surface wavefunctions localized within the hole and electron bands. By combining computational first-principles results with theoretical analyses, this project aims to explore the potential applications of topological insulators as quantum processing units that can operate in noisy environments.
References
(1) Mercado et al. (2024)
(2) Zhang, K. et al. (2024)
(3) Jamali, Mahdi et al. (2014)
(4) Zhang, H et al. (2009)
| I am the presenting author | Yes |
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