TY - JOUR
T1 - Direct evidence for Cooper pairing without a spectral gap in a disordered superconductor above Tc
AU - Bastiaans, Koen M.
AU - Chatzopoulos, Damianos
AU - Ge, Jian Feng
AU - Tromp, Willem O.
AU - van Ruitenbeek, Jan M.
AU - de Visser, Pieter J.
AU - Thoen, David J.
AU - Driessen, Eduard F.C.
AU - Klapwijk, Teunis M.
AU - More Authors, null
PY - 2021
Y1 - 2021
N2 - The idea that preformed Cooper pairs could exist in a superconductor at temperatures higher than its zero-resistance critical temperature (Tc) has been explored for unconventional, interfacial, and disordered superconductors, but direct experimental evidence is lacking. We used scanning tunneling noise spectroscopy to show that preformed Cooper pairs exist up to temperatures much higher than Tc in the disordered superconductor titanium nitride by observing an enhancement in the shot noise that is equivalent to a change of the effective charge from one to two electron charges. We further show that the spectroscopic gap fills up rather than closes with increasing temperature. Our results demonstrate the existence of a state above Tc that, much like an ordinary metal, has no (pseudo)gap but carries charge through paired electrons.
AB - The idea that preformed Cooper pairs could exist in a superconductor at temperatures higher than its zero-resistance critical temperature (Tc) has been explored for unconventional, interfacial, and disordered superconductors, but direct experimental evidence is lacking. We used scanning tunneling noise spectroscopy to show that preformed Cooper pairs exist up to temperatures much higher than Tc in the disordered superconductor titanium nitride by observing an enhancement in the shot noise that is equivalent to a change of the effective charge from one to two electron charges. We further show that the spectroscopic gap fills up rather than closes with increasing temperature. Our results demonstrate the existence of a state above Tc that, much like an ordinary metal, has no (pseudo)gap but carries charge through paired electrons.
UR - http://www.scopus.com/inward/record.url?scp=85118307467&partnerID=8YFLogxK
U2 - 10.1126/science.abe3987
DO - 10.1126/science.abe3987
M3 - Article
AN - SCOPUS:85118307467
SN - 0036-8075
VL - 374
SP - 608-+
JO - Science
JF - Science
IS - 6567
ER -