Abstract
We study the temperature-dependent electronic Raman response of a slightly underdoped single crystal with a superconducting critical temperature . Our main finding is that the superconducting pair-breaking peak is associated with a dip on its higher-energy side, disappearing together at . This result reveals a key aspect of the unconventional pairing mechanism: spectral weight lost in the dip is transferred to the pair-breaking peak at lower energies. This conclusion is supported by cellular dynamical mean-field theory on the Hubbard model, which is able to reproduce all the main features of the Raman response and explain the peak-dip behavior in terms of a nontrivial relationship between the superconducting gap and the pseudogap.
- Received 26 January 2016
DOI:https://doi.org/10.1103/PhysRevLett.116.197001
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