Generalized XY model with competing antiferromagnetic and antinematic interactions

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Phase Transitions

Background:

• The study explores the critical behavior of the antiferromagnetic (AF) XY model on a square lattice.
• It specifically investigates the influence of q-order antinematic (AN_q) interactions.

Purpose of the Study:

• To analyze how AN_q interactions modify the phase diagram topology of the AF XY model.
• To compare the behavior of AF-AN_q models with ferromagnetic (FM)-N_q models.

Main Methods:

• Theoretical analysis of the AF XY model with varying q-order antinematic interactions.
• Phase diagram mapping and comparison between different interaction types (AF vs. FM) and q values.

Main Results:

• Phase diagram topology differs between AF-AN_q and FM-N_q models, especially for even q.
• For odd q, phase diagrams are similar, with phases appearing on both AF sublattices.
• A novel canted (C)AF phase emerges at low temperatures due to competing AF and AN_q ordering tendencies, absent in FM-N_q models.

Conclusions:

• The critical behavior of AF-AN_q models is distinct from FM-N_q models, particularly for even q.
• The newly identified canted (C)AF phase represents a unique low-temperature state in these systems.
• Phase transitions to the canted phase exhibit Berezinskii-Kosterlitz-Thouless characteristics.