專題演講 Seminar

2018/10/30(Tue)     14:00 -16:00    五樓第一會議室 5F, 1st Meeting Room

Title

Uncovering the bulk Fermi surfaces of the topological semimetals via de Hass-van Alphen effect

Speaker

陳冠文先生 (佛羅里達州立大學物理學系)

Mr. Kuan-Wen Chen (Department of Physics, Florida State University)

Abstract

The de Hass-van Alphen (dHvA) effect is a powerful tool that has been used to investigate the metallic band structures and Fermi surfaces of many different materials during the last 90 years. Recently, it gained new importance during efforts to uncover the novel band structures and Berry’s phases in systems with topologically protected electronic states. In this talk, I will focus on the dHvA effect measured using torque magnetomery in the type II Dirac semimetal family of materials (V,Nb,Ta)Al3. Our measurements reveal the existence of tilted Dirac cones with Dirac type-II nodes located at 100, 230 and 250 meV away from the Fermi surface for VAl3, NbAl3, TaAl3 respectively. These results are consistent with earlier band structure calculations, which also predict a non-trivial electronic topology. However, for all three compounds we find that the cyclotron orbits on the Fermi surfaces, including an orbit nearly enclosing the Dirac type-II node, yield trivial Berry phases. We will show that in order to determine the Berry phases, the overall understanding of the topology of the Fermi surfaces and the g-factors are required.

References:
[1] K.-W. Chen1,2, X. Lian1,2, Y. Lai1,2, N. Aryal1,2, Y.-C. Chiu1,2, W. Lan1,2, D. Graf1, E. Manousakis1,2, R. E. Baumbach1,2, and L. Balicas1,2, Phys. Rev. Lett. 120, 206401(2018).

[2] K.-W. Chen1,2, N. Aryal1,2, J. Dai3, D. Graf1, S. Zhang1,2, S. Das1,2, P. Le Fèvre4, F. Bertran4, R. Yukawa5, K. Horiba5, H. Kumigashira5, E. Frantzeskakis3, F. Fortuna3, L. Balicas1,2, A. F. Santander-Syro3, E. Manousakis1,2, and R. E. Baumbach1,2, Phys. Rev. B 97, 165112 (2018).

[3] K.-W. Chen1,2, Y. Lai1,2, Y.-C. Chiu1,2, S. Steven6, T. Besara1, D. Graf1, T. Siegrist1,7, T. E. Albrecht-Schmitt6, L. Balicas1,2, and R. E. Baumbach1,2, Phys. Rev. B 96, 014421 (2017).

[4] K-W. Chen1,2, S Das1,2, D Rhodes1,2, S Memaran1,2, T Besara1, T Siegrist1,7, E Manousakis1,2, L Balicas1,2 and R E Baumbach1,2, Journal of Physics: Condensed Matter 28, 14LT01(2016).

[5] K. -W. Chen1,2, D. Graf1, T. Besara1, A. Gallagher1,2, N. Kikugawa1,8, L. Balicas1,2, T. Siegrist1,7, A. Shekhter1, and R. E. Baumbach1,2, Phys. Rev. B 93, 045118 (2016).

1). National High Magnetic Field Laboratory, Florida State University, Florida, USA
2). Department of Physics, Florida State University, Florida, USA
3). CSNSM, Universié Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay Cedex, France
4). Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192 Gif-sur-Yvette, France
5). Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Japan
6). Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
7). Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
8). National Institute for Materials Science, 3-13 Sakura, Tsukuba, Japan

Language

演講語言 (Language): in English