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arXiv 2209.04743cond-mat.supr-concond-mat.mes-hall
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用电导测量探测扩散多端约瑟夫森结器件的拓扑能带结构

Probing the topological band structure of diffusive multiterminal Josephson junction devices with conductance measurements

Venkat Chandrasekhar

摘要:

与两个超导体接触的干净的正常金属中的Andreev束缚态的能量以超导体之间的超导相的差$Δϕ$分散,其方式与一维晶体中的电子的能量以电子的晶体动量$k$分散的方式大致相同。具有$n$超导体的正常金属映射到$n-1$维晶体上,每个维度对应于特定一对超导体之间的相位差$ϕ_i$。作为相位差$\{Δϕ_i\}$的函数的所得到的能带结构已经被提出具有拓扑性质,具有由准粒子谱中的间隙闭合的区域分离的不同陈数表征的间隙区域。对于与多个超导体接触的扩散正常金属,也预测了具有$\{Δϕ_i\}$的准粒子谱的类似复杂演化。在这里,我们表明,这种系统的费米能量的态密度的变化可以直接探测相对简单的电导测量,允许快速表征的能谱。

英文摘要:

The energy of an Andreev bound state in a clean normal metal in contact with two superconductors disperses with the difference $Δϕ$ in the superconducting phase between the superconductors in much the same way as the energies of electrons in a one-dimensional crystal disperse with the crystal momentum $k$ of the electrons. A normal metal with $n$ superconductors maps on to a $n-1$ dimensional crystal, each dimension corresponding to the phase difference $ϕ_i$ between a specific pair of superconductors. The resulting band structure as a function of the phase differences $\{Δϕ_i\}$ has been proposed to have a topological nature, with gapped regions characterized by different Chern numbers separated by regions where the gap in the quasiparticle spectrum closes. A similar complex evolution of the quasiparticle spectrum with $\{Δϕ_i\}$ has also been predicted for diffusive normal metals in contact with multiple superconductors. Here we show that the variation of the density of states at the Fermi energy of such a system can be directly probed by relatively simple conductance measurements, allowing rapid characterization of the energy spectrum.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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