Spin separation in the half-filled fractional topological insulator

Article

关键词: PHASE;    EXCITATION;    MODES;    STATE;   

DOI  :  10.1103/PhysRevB.99.115131

来源: SCIE

【 摘 要 】

All topological insulators observed so far are the lattice analogs of the integer quantum Hall states with time-reversal symmetry, composed of two decoupled copies of the Chern insulator with opposite chiralities for different spins. The fractional topological insulator (FTI) has been similarly envisioned as being composed of two decoupled copies of the fractional Chern insulator (FCI), which is in turn the lattice analog of the fractional quantum Hall state (FQHS). An important question is if such a vision can be realized for the Coulomb interaction, whose strength is irrespective of spin. To address this question, we investigate the effects of the interspin correlation in the spin-holomorphic Landau levels, where electrons with one spin reside in the usual holomorphic lowest Landau level, while those with the other in the antiholomorphic counterpart. By performing exact diagonalization of the Coulomb interaction Hamiltonian in the spin-holomorphic Landau levels, here, we show that no fractionally filled states in the spin-holomorphic Landau levels can occur as two decoupled copies of the FQHS, suggesting that no FTIs can occur as those of the FCI in the lattice either. Fractionally filled states in this system are generally compressible except at half filling, where a transport gap develops with spontaneous breaking of the space rotational symmetry in the thermodynamic limit, leading to the spatial separation of different spins, i.e., spin separation. It is predicted that there is a novel bulk-edge correspondence at half filling, representing the hallmark of the half-filled spin-separated FTI.

【 授权许可】

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