Three-dimensional topological phases in a layered honeycomb spin-orbital model - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




Three-dimensional topological phases in a layered honeycomb spin-orbital model - Condensed Matter > Mesoscale and Nanoscale Physics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present an exactly solvable spin-orbital model based on the Gamma-matrixgeneralization of a Kitaev-type Hamiltonian. In the presence of small magneticfields, the model exhibits a critical phase with a spectrum characterized bytopologically protected Fermi points. Upon increasing the magnetic field, Fermipoints carrying opposite topological charges move toward each other andannihilate at a critical field, signaling a phase transition into a gappedphase with trivial topology in three dimensions. On the other hand, bysubjecting the system to a staggered magnetic field, an effective time-reversalsymmetry essential to the existence of three-dimensional topological insulatorsis restored in the auxiliary free fermion problem. The nontrivial topology ofthe gapped ground state is characterized by an integer winding number andmanifests itself through the appearance of gapless Majorana fermions confinedto the two-dimensional surface of a finite system.



Author: Gia-Wei Chern

Source: https://arxiv.org/







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