• A
  • A
  • A
  • ABC
  • ABC
  • ABC
  • А
  • А
  • А
  • А
  • А
Regular version of the site

Article

Screening of pair fluctuations in superconductors with coupled shallow and deep bands: A route to higher-temperature superconductivity

Salasnich L., Shanenko A., Vagov A., Aguiar J. A., Perali A.

A combination of strong Cooper pairing and weak superconducting fluctuations is crucial to achieve and

stabilize high-Tc superconductivity. We demonstrate that a coexistence of a shallow carrier band with strong

pairing and a deep band with weak pairing, together with the Josephson-like pair transfer between the bands to

couple the two condensates, realizes an optimal multicomponent superconductivity regime: it preserves strong

pairing to generate large gaps and a very high critical temperature but screens the detrimental superconducting

fluctuations, thereby suppressing the pseudogap state. Surprisingly, we find that the screening is very efficient

even when the interband coupling is very small. Thus, a multiband superconductor with a coherent mixture

of condensates in the BCS regime (deep band) and in the BCS-BEC crossover regime (shallow band) offers a

promising route to higher critical temperatures.