Genesis of the Floquet Hofstadter butterfly

S. H. Kooi, A. Quelle, W. Beugeling, and C. Morais Smith
Phys. Rev. B 98, 115124 – Published 14 September 2018

Abstract

We investigate theoretically the spectrum of a graphenelike sample (honeycomb lattice) subjected to a perpendicular magnetic field and irradiated by circularly polarized light. This system is studied using the Floquet formalism, and the resulting Hofstadter spectrum is analyzed for different regimes of the driving frequency. For lower frequencies, resonances of various copies of the spectrum lead to intricate formations of topological gaps. In the Landau-level regime, new winglike gaps emerge upon reducing the driving frequency, thus revealing the possibility of dynamically tuning the formation of the Hofstadter butterfly. In this regime, an effective model may be analytically derived, which allows us to retrace the energy levels that exhibit avoided crossings and ultimately lead to gap structures with a winglike shape. At high frequencies, we find that gaps open for various fluxes at E=0, and upon increasing the amplitude of the driving, gaps also close and reopen at other energies. The topological invariants of these gaps are calculated and the resulting spectrum is elucidated. We suggest opportunities for experimental realization and discuss similarities with Landau-level structures in nondriven systems.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 20 March 2018
  • Revised 9 August 2018

DOI:https://doi.org/10.1103/PhysRevB.98.115124

©2018 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

S. H. Kooi1, A. Quelle1, W. Beugeling2, and C. Morais Smith1

  • 1Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
  • 2Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 98, Iss. 11 — 15 September 2018

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×