Projects per year
We experimentally measure the band dispersions of topological Dirac semimetal Na3Bi using Fourier-transform scanning tunneling spectroscopy to image quasiparticle interference on the (001) surface of molecular-beam epitaxy-grown Na3Bi thin films. We find that the velocities for the lowest-lying conduction and valence bands are 1.6×106ms-1 and 4.2×105ms-1 respectively, significantly higher than previous theoretical predictions. We compare the experimental band dispersions to the theoretical band structures calculated using an increasing hierarchy of approximations of self-energy corrections due to interactions: generalized gradient approximation (GGA), meta-GGA, Heyd-Scuseria-Ernzerhof exchange-correlation functional (HSE06), and GW methods. We find that density functional theory methods generally underestimate the electron velocities. However, we find significantly improved agreement with an increasingly sophisticated description of the exchange and interaction potential, culminating in reasonable agreement with experiments obtained by the GW method. The results indicate that exchange-correlation effects are important in determining the electronic structure of this Na3Bi, and are likely the origin of the high velocity. The electron velocity is consistent with recent experiments on ultrathin Na3Bi and also may explain the ultrahigh carrier mobility observed in heavily electron-doped Na3Bi.
Fuhrer, M., Bao, Q., Culcer, D., Davis, M., Davis, J. A., Hamilton, A., Helmerson, K., Klochan, O., Medhekar, N., Ostrovskaya, E., Parish, M., Schiffrin, A., Seidel, J., Sushkov, O., Valanoor, N., Wang, X., Galitskiy, V., Gurarie, V., Hannon, J., Höfling, S., Hone, J., Rule, K. C., Krausz, F., Littlewood, P., MacDonald, A., Neto, A., Oezyilmaz, B., Paglione, J., Phillips, W., Spielman, I., Tadich, A., Xue, Q., Cole, J., Perali, A., Neilson, D., Sek, G., Gaston, N., Hodgkiss, J. M., Tang, M., Karel, J., Nguyen, T., Adam, S., Granville, S., Kumar, P. & Daeneke, T.
Australian Research Council (ARC), Monash University – Internal School Contribution, Monash University – Internal Department Contribution, Monash University – Internal Faculty Contribution, Monash University – Internal University Contribution, University of Wollongong, University of Queensland , Tsinghua University, University of New South Wales (UNSW), Australian National University (ANU), RMIT University, Swinburne University of Technology
29/06/17 → 28/06/24
17/06/16 → 31/12/19