Phononic Helical Nodal Lines with PT Protection in MoB2

T. T. Zhang, H. Miao, Q. Wang, J. Q. Lin, Y. Cao, G. Fabbris, A. H. Said, X. Liu, H. C. Lei, Z. Fang, H. M. Weng, and M. P. M. Dean
Phys. Rev. Lett. 123, 245302 – Published 13 December 2019
PDFHTMLExport Citation

Abstract

While condensed matter systems host both fermionic and bosonic quasiparticles, reliably predicting and empirically verifying topological states is only mature for Fermionic electronic structures, leaving topological Bosonic excitations sporadically explored. This is unfortunate, as Bosonic systems such as phonons offer the opportunity to assess spinless band structures where nodal lines can be realized without invoking special additional symetries to protect against spin-orbit coupling. Here we combine first-principles calculations and meV-resolution inelastic x-ray scattering to demonstrate the first realization of parity-time reversal symmetry protected helical nodal lines in the phonon spectrum of MoB2. This structure is unique to phononic systems as the spin-orbit coupling present in electronic systems tends to lift the degeneracy away from high-symmetry locations. Our study establishes a protocol to accurately identify topological Bosonic excitations, opening a new route to explore exotic topological states in crystalline materials.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 16 August 2019

DOI:https://doi.org/10.1103/PhysRevLett.123.245302

© 2019 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsInterdisciplinary PhysicsStatistical Physics & Thermodynamics

Authors & Affiliations

T. T. Zhang1,2,3,4, H. Miao5,*, Q. Wang6, J. Q. Lin1,5,2,7, Y. Cao8, G. Fabbris9, A. H. Said9, X. Liu7, H. C. Lei6,†, Z. Fang1,10, H. M. Weng1,10,‡, and M. P. M. Dean5,§

  • 1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • 2University of Chinese Academy of Sciences, Beijing 100049, China
  • 3Department of Physics, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551, Japan
  • 4Tokodai Institute for Element Strategy, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
  • 5Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA
  • 6Department of Physics and Beijing Key Laboratory of Opto-Electronic Functional Materials and Micro-devices, Renmin University of China, Beijing, China
  • 7School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
  • 8Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
  • 9Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
  • 10Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China

  • *hmiao@bnl.gov
  • hlei@ruc.edu.cn
  • hmweng@iphy.ac.cn
  • §mdean@bnl.gov

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 123, Iss. 24 — 13 December 2019

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×