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Electric field assisted amplification of magnetic fields in tilted Dirac cone systems

Jafari, S. A ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1103/PhysRevB.100.045144
  3. Publisher: American Physical Society , 2019
  4. Abstract:
  5. We show that the continuum limit of the tilted Dirac cone in materials such as 8-Pmmn borophene and layered organic conductor α-(BEDT-TTF)2I3 corresponds to deformation of the Minkowski space-time of Dirac materials. From its Killing vectors we construct an emergent tilted-Lorentz (t-Lorentz) symmetry group for such systems. As an example of the t-Lorentz transformations we obtain the exact solution of the Landau bands for a crossed configuration of electric and magnetic fields. For any given tilt parameter 0≤ζ<1, if the ratio χ=vFBz/Ey of the crossed magnetic and electric fields satisfies χ≥1+ζ, one can always find appropriate t-boosts in both valleys labeled by τ=±1 in such a way that the electric field can be t-boosted away, whereby the resulting pure effective magnetic field Bzτ governs the Landau level spectrum around each valley τ. The effective magnetic field in one of the valleys is always larger than the applied perpendicular magnetic field. This amplification comes at the expense of of diminishing the effective field in the opposite valley and can be detected in various quantum oscillation phenomena in tilted Dirac cone systems. Tuning the ratio of electric and magnetic fields to χmin=1+ζ leads to valley selective collapse of Landau levels. Our geometric description of the tilt in Dirac systems reveals an important connection between the tilt and an incipient "rotating source" when the tilt parameter can be made to depend on space-time in a certain way. © 2019 American Physical Society
  6. Keywords:
  7. Electric fields ; Landforms ; Electric and magnetic fields ; Geometric description ; Layered organic conductors ; Lorentz transformations ; Magnetic and electric fields ; Minkowski space-time ; Perpendicular magnetic fields ; Quantum oscillations ; Magnetic fields
  8. Source: Physical Review B ; Volume 100, Issue 4 , 2019 ; 24699950 (ISSN)
  9. URL: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.100.045144