Unconventional spin-charge phase separation in a model 2D cuprate
| Autor: | Yu. D. Panov, K. S. Budrin, A. A. Chikov, A. S. Moskvin |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Physics Superconductivity Phase transition Physics and Astronomy (miscellaneous) Condensed matter physics Monte Carlo method Charge (physics) 01 natural sciences Effective nuclear charge 0103 physical sciences Antiferromagnetism Condensed Matter::Strongly Correlated Electrons 010306 general physics Ground state Spin-½ |
| Zdroj: | JETP Letters. 106:440-445 |
| ISSN: | 1090-6487 0021-3640 |
| DOI: | 10.1134/s002136401719002x |
| Popis: | In this work, we address a challenging problem of a competition of charge and spin orders for high-T c cuprates within a simplified 2D spin-pseudospin model which takes into account both conventional Heisenberg Cu2+−Cu2+ antiferromagnetic spin exchange coupling (J) and the on-site (U) and intersite (V) charge correlations in the CuO2 planes with the on-site Hilbert space reduced to only three effective charge states (nominally Cu1+;2+;3+). We performed classical Monte Carlo calculations for large square lattices implying the mobile doped charges and focusing on a case of a small intersite repulsion V ≪ J. The on-site attraction (U 0) the homogeneous ground state antiferromagnetic solutions of the doped system found in a mean-field approximation are shown to be unstable with respect to a phase separation with the charge and spin subsystems behaving like immiscible quantum liquids. Puzzlingly, with lowering the temperature one can observe two sequential phase transitions: first, an antiferromagnetic ordering in the spin subsystem diluted by randomly distributed charges, then, a charge condensation in the charge droplets. The effects are illustrated by the Monte Carlo calculations of the specific heat and longitudinal magnetic susceptibility. |
| Databáze: | OpenAIRE |
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