2009/12/31 by Gia-Wei Chern · 28 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Fermion #Gapless playback #Ground state #Hamiltonian (control theory) #MAJORANA #Majorana fermion #Mathematics #Physics #Quantum #Quantum many-body systems #Quantum mechanics #Topological Materials and Phenomena #Topological order #Topology (electrical circuits) #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.81.125134
published in Physical Review B 81(12) (American Physical Society) · 10 pages, 5 figures
arxiv created 2010/02/11 · openalex publication_date 2010/03/31 · arxiv updated 2010/07/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present an exactly solvable spin-orbital model based on the Gamma-matrix generalization of a Kitaev-type Hamiltonian. In the presence of small magnetic fields, the model exhibits a critical phase with a spectrum characterized by topologically protected Fermi points. Upon increasing the magnetic field, Fermi points carrying opposite topological charges move toward each other and annihilate at a critical field, signaling a phase transition into a gapped phase with trivial topology in three dimensions. On the other hand, by subjecting the system to a staggered magnetic field, an effective time-reversal symmetry essential to the existence of three-dimensional topological insulators is restored in the auxiliary free fermion problem. The nontrivial topology of the gapped ground state is characterized by an integer winding number and manifests itself through the appearance of gapless Majorana fermions confined to the two-dimensional surface of a finite system.