We experimentally study the electrical transport properties of Ge/Si core/shell nanowire device with two superconducting leads in the Coulomb blockade regime. Anomalous zero field magnetoconductance peaks are observed for the first time at the gate voltages where Coulomb blockade oscillation peaks present. Many evidences indicate this feature is due to Andreev reflection enhanced phase coherent single hole tunneling through the quantum dot, which can be suppressed by an external magnetic field without destroying the superconducting states in the electrodes.
@article{arxiv.1005.5077,
title = {Andreev reflection enhanced single hole tunneling in Ge/Si core/shell nanowire quantum dot},
author = {Xiao-Jie Hao and Guo-Ping Guo and Hai-Ou Li and Cheng Zhou and Gang Cao and Guang-Can Guo and Wayne Y. Fung and Zhongqing Ji and Wei Lu and Tao Tu},
journal= {arXiv preprint arXiv:1005.5077},
year = {2010}
}