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Prof. Dr. Evandro V. L. de Mello, UFF – Giant proximity effect due to charge density waves in cuprate superconductors – 1º de Julho 14:00
1 de julho:14:00 - 15:00
Cuprate superconductors are well known for their high critical temperatures and unusual properties like giant proximity effect (GPE), that is the ability of a supercurrent to flow through large non-superconducting regions. These experiments contradict conventional theories of supercurrent exponential suppression for barrier thickness larger than the superconducting coherence length. Here, we propose that this anomalous behavior is due to the presence of short-range, incommensurate static charge-density-wave instabilities (CDW) simulated by a Ginzburg-Landau (GL) free energy. The charge fluctuations due to the GL potential induce local Cooper pairs in alternating charge domains, forming an array of nanoscopic Josephson junctions. The local superconducting amplitude remains finite above the critical temperatures and, at low temperatures, reproduces the superfluid densities and the GPE critical currents.