Sergio Caprara (Dipartimento di Fisica, Sapienza Università di Roma)

Jeudi 18 Mai 2017 à 14h00
Amphi Holweck, Esc C
1ème etage

Dynamical charge density waves rule the phase diagram of cuprates

In the last few years charge density waves (CDWs) have been ubiquitously observed in high- temperature superconducting cuprates and are now the most investigated among the competing orders in the still hot debate on these systems. A wealth of new experimental data raises several fundamental issues that challenge the various theoretical proposals. We here relate our mean field instability line T_CDW of a strongly correlated Fermi Liquid to the pseudogap T*(p) line, marking in this way the onset of CDW-fluctuations. These fluctuations reduce strongly the mean field critical line. Controlling this reduction via an infrared frequency cut-off related to the characteristic time of the probes, we account for the complex experimental temperature vs. doping phase diagram. We provide a coherent scenario explaining why different CDW onset curves are observed by different experimental probes and seem to extrapolate at zero temperature into seemingly different quantum critical points (QCPs) in the intermediate and overdoped region. The nearly singular anisotropic scattering mediated by these fluctuations also accounts for the rapid changes of the Hall number seen in experiments and provides the first necessary step for a possible Fermi surface reconstruction fully establishing at lower doping. Finally we show that phase fluctuations of the CDWs, which are enhanced in the presence of strong correlations near the Mott insulating phase, naturally account for the disappearance of the CDWs at low doping with yet another QCP as seen by the experiments.

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