Suppression of the superconductivity in ultrathin amorphous Mo78Ge22 films observed by STM
Suppression of the superconductivity in ultrathin amorphous Mo78Ge22 films observed by STM
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STM 观察到的超薄非晶 Mo78Ge22 薄膜中超导性的抑制
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
P. Samuely
中科院分区：
文献类型：
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作者：
D. Lotnyk;O. Onufriienko;T. Samuely;O. Shylenko;V. Komanický;P. Szabó;A. Feher;P. Samuely
与超导体接触时，普通金属会因安德烈夫反射而改变其特性。在当前的工作中，超导体-普通金属Mo78Ge22-Au双层的局部态密度（LDOS）是通过从Au一侧应用STM来研究的。在硅酸盐玻璃基板上制备了三个双层，该基板由 100、10 和 5 nm MoGe 薄膜组成，并始终覆盖 5 nm Au 层。隧道光谱是在 0.5 至 7 K 的温度下测量的。形貌与归一化零偏压电导之间的二维互相关表明 100 至 10nm MoGe 薄膜和 Au 层之间存在邻近效应，其中观察到的超导带隙略小于块体 MoGe 的带隙。最薄的 5nm MoGe 层对 Au 的影响导致间隙小得多，而且 LDOS 显示几乎完全抑制的相干峰。这是由于 MoGe 薄膜和衬底之间的界面处自旋翻转过程的强烈破对效应。
In contact with a superconductor a normal metal modifies its properties due to Andreev reflection. In the current work the local density of states (LDOS) of superconductor–normal metal Mo78Ge22–Au bilayers are studied by means of STM applied from the Au side. Three bilayers have been prepared on silicate glass substrate consisting of 100, 10 and 5 nm MoGe thin films covered always by 5 nm Au layer. The tunneling spectra were measured at temperatures from 0.5 to 7 K. The two-dimensional cross-correlation between topography and normalized zero-bias conductance indicates a proximity effect between 100 and 10 nm MoGe thin films and Au layer where a superconducting gap slightly smaller than that of bulk MoGe is observed. The effect of the thinnest 5 nm MoGe layer on Au leads to much smaller gap moreover the LDOS reveals almost completely suppressed coherence peaks. This is attributed to a strong pair-breaking effect of spin-flip processes at the interface between MoGe films and the substrate.