Brand J, Ribeiro P, Néel N, Kirchner S, Kröger J
Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany.
CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
Phys Rev Lett. 2017 Mar 10;118(10):107001. doi: 10.1103/PhysRevLett.118.107001. Epub 2017 Mar 9.
Charge transport has been examined in junctions comprising the normal-metal tip of a low-temperature scanning tunneling microscope, the surface of a conventional superconductor, and adsorbed C_{60} molecules. The Bardeen-Cooper-Schrieffer energy gap gradually evolves into a zero-bias peak with decreasing electrode separation. The peak is assigned to the spectroscopic signature of Andreev reflection. The conductance due to Andreev reflection is determined by the atomic termination of the tip apex and the molecular adsorption orientation. Transport calculations unveil the finite temperature and the strong molecule-electrode hybridization as the origin to the surprisingly good agreement between spectroscopic data and the Blonder-Tinkham-Klapwijk model that was conceived for macroscopic point contacts.
在由低温扫描隧道显微镜的普通金属尖端、传统超导体表面和吸附的C₆₀分子组成的结中，对电荷传输进行了研究。随着电极间距减小，巴丁-库珀-施里弗能隙逐渐演变成零偏置峰。该峰被归因于安德列夫反射的光谱特征。由于安德列夫反射产生的电导由尖端顶点的原子终止和分子吸附取向决定。输运计算揭示了有限温度和强分子-电极杂化是光谱数据与为宏观点接触所设想的布隆德-廷克汉姆-克拉普维克模型之间惊人良好一致性的根源。
