Two-stage melting of an intercomponent Potts long-range order in two dimensions

Article

关键词: MATRIX PRODUCT STATES;    PHASE-TRANSITIONS;    HELICITY MODULUS;    HEXATIC ORDER;    HEAT-CAPACITY;    MONTE-CARLO;    SUPERFLUIDITY;    DENSITY;   

DOI  :  10.1103/PhysRevB.107.165129

来源: SCIE

【 摘 要 】

The interplay of topology and competing interactions can induce enriched phases and phase transitions at finite temperatures. We consider a weakly coupled two-dimensional hexatic-nematic XY model with a relative Z3 Potts degrees of freedom, and apply the matrix product state method to solve this model rigorously. Since the partition function is expressed as a product of two-legged one-dimensional transfer matrix operator, an entanglement entropy of the eigenstate corresponding to the maximal eigenvalue of this transfer operator can be used as a stringent criterion to determine various phase transitions precisely. At low temperatures, the intercomponent Z3 Potts long-range order (LRO) exists, indicating that the hexatic and nematic fields are locked together and their respective vortices exhibit quasi-LRO. In the hexatic regime, below the BKT transition of the hexatic vortices, the intercomponent Z3 Potts LRO appears, accompanying the binding of nematic vortices. In the nematic regime, however, the intercomponent Z3 Potts LRO undergoes a two-stage melting process. An intermediate Potts liquid phase emerges between the Potts ordered and disordered phases, characterized by an algebraic correlation with formation of charge-neutral pairs of both hexatic and nematic vortices. These two-stage phase transitions are associated with the proliferation of the domain walls and vortices of the relative Z3 Potts variable, respectively. Our results thus provide a prototype example of two-stage melting of a two-dimensional LRO driven by multiple topological defects.

【 授权许可】

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