Pilgram S, Rice T M, Sigrist M
Theoretische Physik, ETH Zurich, CH-8093 Zürich, Switzerland.
Phys Rev Lett. 2006 Sep 15;97(11):117003. doi: 10.1103/PhysRevLett.97.117003.
The tunneling path between the CuO2 layers in cuprate superconductors and a scanning-tunneling-microscope tip passes through a barrier made from other oxide layers. This opens up the possibility that inelastic processes in the barrier contribute to the tunneling spectra. Such processes cause one or possibly more peaks in the second derivative current-voltage spectra displaced by phonon energies from the density of states singularity associated with superconductivity. Calculations of inelastic processes generated by apical O phonons show good qualitative agreement with recent experiments reported by Lee et al. Further tests to discriminate between these inelastic processes and coupling to planar phonons are proposed.
铜酸盐超导体中CuO₂层与扫描隧道显微镜尖端之间的隧穿路径穿过由其他氧化物层构成的势垒。这使得势垒中的非弹性过程对隧穿谱有贡献成为可能。此类过程会在二阶导数电流 - 电压谱中导致一个或可能更多个峰，这些峰相对于与超导相关的态密度奇点因声子能量而发生位移。对顶氧声子产生的非弹性过程的计算与Lee等人近期报道的实验结果在定性上吻合良好。文中还提出了进一步的测试，以区分这些非弹性过程与与面内声子的耦合。
