TY - JOUR
T1 - Origin of the Anomalous Electronic Shot Noise in Atomic-Scale Junctions
AU - Mu, Anqi
AU - Shein-Lumbroso, Ofir
AU - Tal, Oren
AU - Segal, Dvira
N1 - D.S. acknowledges the Natural Sciences and Engineering Research Council (NSERC) of Canada Discovery Grant and the Canada Chairs Program. O.T. appreciates the support of the Harold Perlman family, and acknowledges funding by a research grant from Dana and Yossie Hollander, the Israel Science Foundation (grant number 1089/15), and the Minerva Foundation (grant number 120865).
PY - 2019/10/3
Y1 - 2019/10/3
N2 - Fluctuations pose fundamental limitations in making sensitive measurements, yet at the same time, noise unravels properties that are inaccessible at the level of the averaged signal. In electronic devices, shot noise arises from the discrete nature of charge carriers, and it increases linearly with averaged current (or applied bias for ohmic conductors) according to the celebrated Schottky formula. Nonetheless, measurements of shot noise in atomic-scale junctions at high voltage reveal significant nonlinear (anomalous) behavior, which varies from sample to sample, and has no specific trend. Here, we provide a viable, unifying explanation for these diverse observations based on the theory of quantum coherent transport. Our formula for the anomalous shot noise relies on-and allows us to resolve-two key characteristics of a conducting junction: The structure of the transmission function at the vicinity of the Fermi energy and the asymmetry of the bias voltage drop at the contacts. We test our theory on high voltage shot noise measurements on Au atomic scale junctions and demonstrate a quantitative agreement, recovering both the enhancement and suppression of shot noise as observed in different junctions. The good theory-experiment correspondence supports our modeling and emphasizes that the asymmetry of the bias drop on the contacts is a key factor in nanoscale electronic transport, which may substantially impact electronic signals even in incomplex structures.
AB - Fluctuations pose fundamental limitations in making sensitive measurements, yet at the same time, noise unravels properties that are inaccessible at the level of the averaged signal. In electronic devices, shot noise arises from the discrete nature of charge carriers, and it increases linearly with averaged current (or applied bias for ohmic conductors) according to the celebrated Schottky formula. Nonetheless, measurements of shot noise in atomic-scale junctions at high voltage reveal significant nonlinear (anomalous) behavior, which varies from sample to sample, and has no specific trend. Here, we provide a viable, unifying explanation for these diverse observations based on the theory of quantum coherent transport. Our formula for the anomalous shot noise relies on-and allows us to resolve-two key characteristics of a conducting junction: The structure of the transmission function at the vicinity of the Fermi energy and the asymmetry of the bias voltage drop at the contacts. We test our theory on high voltage shot noise measurements on Au atomic scale junctions and demonstrate a quantitative agreement, recovering both the enhancement and suppression of shot noise as observed in different junctions. The good theory-experiment correspondence supports our modeling and emphasizes that the asymmetry of the bias drop on the contacts is a key factor in nanoscale electronic transport, which may substantially impact electronic signals even in incomplex structures.
UR - http://www.scopus.com/inward/record.url?scp=85072930630&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/acs.jpcc.9b06766
DO - https://doi.org/10.1021/acs.jpcc.9b06766
M3 - مقالة
SN - 1932-7447
VL - 123
SP - 23853
EP - 23862
JO - Journal of Physical chemistry c
JF - Journal of Physical chemistry c
IS - 39
ER -