Analytical solution of the finite-length Kitaev chain coupled to a quantum dot

Article

关键词: MAJORANA BOUND-STATES;    ZERO MODES;    NANOWIRE;    SUPERCONDUCTOR;    FERMIONS;    SIGNATURE;   

DOI  :  10.1103/PhysRevB.99.094523

来源: SCIE

【 摘 要 】

We solve analytically the problem of a finite-length Kitaev chain coupled to a quantum dot (QD) which extends the standard Kitaev chain problem to the quantum dot-semiconductor-superconductor (QD-SM-SC) nanowire heterostructure currently under intense investigation for possible occurrence of Majorana zero modes (MZMs). As a first step we obtain the analytical solution of the finite-length Kitaev chain without the quantum dot which to the best of our knowledge has also not appeared before. Our full solution of the Kitaev chain coupled to a quantum dot reveals the emergence of a robust near-zero-energy Andreev bound state (ABSs) localized in the quantum dot region as the generic lowest energy solution in the topologically trivial phase. By contrast in the Kitaev chain without the quantum dot such a solution does not exist. The robustness of the ABS in the topologically trivial phase is due to a partial spatial decoupling of the component Majorana bound states (MBSs) over the length of the dot potential. As a result the signatures of the ABS in measurements that couple locally to the quantum dot e.g. tunneling measurements are identical to the signatures of topologically protected MZMs which arise only in the topological superconducting (TS) phase of the Kitaev chain.

【 授权许可】

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