Free energy of a two-liquid system of charge carriers in strongly coupled electron and phonon fields and common nature of three phases in hole-doped cuprates
| Autor: | Myasnikova, A. E., Doronkina, S. V., Arutyunyan, R. R., Dzhantemirov, A. H. |
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| Rok vydání: | 2024 |
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| Druh dokumentu: | Working Paper |
| Popis: | Hole-doped cuprates demonstrate partially coexisting pseudogap, charge density wave (CDW) and superconducting phases. Recently their common nature was supposed due to similar doping dependence of their critical temperatures. In the CDW phase, a large frozen deformation of strongly ionic lattice is observed. Like for a single carrier in a highly polarizable lattice, for multiple carriers in it the choice between delocalized states of all the carriers and autolocalized states of some part of them is determined by minimum of free energy of interacting carrier and phonon fields. Applying variational approach, we calculate free energy of a two-liquid system of carriers with cuprates-like dispersion comprising liquid of autolocalized carriers (large polarons and bipolarons) and Fermi liquid of delocalized carriers. Comparing it with the free energy of pure Fermi liquid and calculating (with standard methods of Bose-liquid theory) a temperature of superfluid transition in the large-bipolaron liquid we identify areas with presence of pseudogap (caused by impact of (bi)polaron potential on delocalized quasiparticles), CDW and superconductivity in a phase diagram. They are in the same places as in hole-doped cuprates, and similarly to cuprates the shape of the calculated phase diagram is stable with respect to wide-range change of the system characteristics. Like in cuprates, the calculated temperature of the superconducting transition increases with the number of conducting planes in the unit cell, the calculated superfluid density decreases with doping at overdoping, and the bipolaron density (together with bipolaronic plasmon energy) saturates at optimal doping. The results obtained allow us to discuss ways of increasing the temperature of the superfluid transition in large-bipolaron liquid and open a possibility of studying the current-carrying state and properties of bipolaron condensate. Comment: 26 pages, 8 figures, submitted to Physical Review B |
| Databáze: | arXiv |
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