Chern insulating phases and thermoelectric properties of EuO/MgO(001) superlattices

Article

关键词: TOPOLOGICAL INSULATORS;    TEMPERATURE;    REALIZATION;    TRANSITION;    ENERGY;    STATE;    MGO;   

DOI  :  10.1103/PhysRevB.103.045135

来源: SCIE

【 摘 要 】

The topological and thermoelectric properties of (EuO)(n)/(MgO)(m)(001) superlattices (SLs) are explored using density functional theory calculations including a Hubbard U term together with Boltzmann transport theory. In (EuO)(1)/(MgO)(3)(001) SL at the lattice constant of MgO a sizable band gap of 0.51 eV is opened by spin-orbit coupling (SOC) due to a band inversion between occupied localized Eu 4f and empty 5d conduction states. This inversion between bands of opposite parity is accompanied by a reorientation in the spin texture along the contour of band inversion surrounding the Gamma point and leads to a Chern insulator with C = -1, also confirmed by the single edge state. Moreover, this Chern insulating phase shows promising thermoelectric properties, e.g., a Seebeck coefficient between 400 and 800 mu V?K-1. A similar SOC-induced band inversion takes place also in the ferromagnetic semimetallic (EuO)(2)/(MgO)(2)(001) SL. Despite the vanishing band gap, it leads to a substantial anomalous Hall conductivity with values up to -1.04 e(2)/h and somewhat lower Seebeck coefficient. Both cases emphasize the relation between nontrivial topological bands and thermoelectricity also in systems with broken inversion symmetry.

【 授权许可】

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