The spatial modulation of the Fermi velocity for gapless Dirac electrons in quantum materials is mathematically equivalent to the problem of massless fermions on a certain class of curved spacetime manifolds. We study null geodesic lensing through these manifolds, which are dominated by curvature singularities, such as nematic singularity walls (where the Dirac cone flattens along one direction). Null geodesics lens across these walls, but do so by perfectly collimating to a local transit angle. Nevertheless, nematic walls can trap null geodesics into stable or metastable orbits characterized by repeated transits. We speculate about the role of induced one-dimensionality for such bound orbits in 2D dirty d-wave superconductivity.
Cited by 3
KÃ¶nye et al., Anisotropic optics and gravitational lensing of tilted Weyl fermions
Phys. Rev. B 107, L201406 (2023) [Crossref]
Bhardwaj et al., Unruh effect and Takagi's statistics inversion in strained graphene
Phys. Rev. B 107, 224310 (2023) [Crossref]
Yekta et al., Tunning the tilt of the Dirac cone by atomic manipulations in 8Pmmn borophene
Commun Phys 6, 46 (2023) [Crossref]