Alpern Hen, Yavilberg Konstantin, Dvir Tom, Sukenik Nir, Klang Maya, Yochelis Shira, Cohen Hagai, Grosfeld Eytan, Steinberg Hadar, Paltiel Yossi, Millo Oded
Racah Institute of Physics and the Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel.
Applied Physics Department the Center for Nanoscience and Nanotechnology , The Hebrew University of Jerusalem , Jerusalem 91904 , Israel.
Nano Lett. 2019 Aug 14;19(8):5167-5175. doi: 10.1021/acs.nanolett.9b01552. Epub 2019 Aug 5.
Hybrid ferromagnetic/superconducting systems are well-known for hosting intriguing phenomena such as emergent triplet superconductivity at their interfaces and the appearance of in-gap, spin-polarized Yu-Shiba-Rusinov (YSR) states bound to magnetic impurities on a superconducting surface. In this work we demonstrate that similar phenomena can be induced on a surface of a conventional superconductor by chemisorbing nonmagnetic chiral molecules. Conductance spectra measured on NbSe flakes over which chiral α-helix polyalanine molecules were adsorbed exhibit, in some cases, in-gap states nearly symmetrically positioned around zero bias that shift with magnetic field, akin to YSR states, as corroborated by theoretical simulations. Other samples show evidence for a collective phenomenon of hybridized YSR-like states giving rise to unconventional, possibly triplet superconductivity, manifested in the conductance spectra by the appearance of a zero bias conductance that diminishes, but does not split, with magnetic field. The transition between these two scenarios appears to be governed by the density of adsorbed molecules.
混合铁磁/超导系统因其在界面处呈现出诸如涌现的三重态超导等有趣现象，以及在超导表面上出现与磁性杂质相关的能隙内自旋极化的汤川-志田-鲁西诺夫（YSR）态而闻名。在这项工作中，我们证明通过化学吸附非磁性手性分子，可以在传统超导体表面诱导出类似的现象。在吸附了手性α-螺旋聚丙氨酸分子的NbSe薄片上测量的电导谱，在某些情况下，显示出在零偏压附近近乎对称分布的能隙态，这些能隙态会随磁场移动，类似于YSR态，理论模拟证实了这一点。其他样品显示出类似YSR态杂化的集体现象的证据，这种现象导致了非常规的、可能是三重态的超导性，在电导谱中表现为零偏压电导的出现，该电导会随磁场减弱但不分裂。这两种情况之间的转变似乎受吸附分子密度的控制。
