2017/12/19 by Berthold Jäck, Jacob Senkpiel, Jäck, Berthold +9
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena #Quantum optics and atomic interactions #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.1712.07172
openalex publication_date 2017/12/19 · openalex created_date 2022/10/04 · openalex updated_date 2026/07/28
Josephson junctions operated in the dynamical Coulomb blockade regime\nrecently gained an significant amount of attention as central building block in\nconcepts to demonstrate the non-Abelian character of Majorana fermions. Its\nphysical properties are strongly affected by the intimate interplay of\nintrinsic quantum fluctuations and environmentally-induced quantum fluctuations\neach of which promoting different Cooper pair transport mechanisms at small\nvoltages around zero. To shed light on the detailed transport mechanisms\noccurring in this type of junction, we performed voltage-biased measurements on\nthe small-capacitance Josephson junction of a scanning tunneling microscope at\nmilli-Kelvin temperatures. The low voltage-regime of experimental\ncurrent-voltage characteristics can be modeled by the two complementary\ndescriptions of phase coherent and incoherent Cooper pair transport, signaling\nthe occurrence of qualitatively different transport mechanisms. This\nobservation receives further support from analyzing the calculated Fano factor\nof the current noise as a probe for correlations in Cooper pair transport,\nfollowing a theoretical proposal. Together our experimental observations and\nrelated data analysis provide a clear signature of coherent Cooper pair\ntransport along with the absence of perfect charge quantized transport around\nzero voltage, as well as of incoherent Cooper pair transport towards higher\nvoltages.\n