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Published on: June 7, 2018
Nematic phase in two-dimensional frustrated systems with power-law decaying interactions
Daniel G Barci1, Leonardo Ribeiro, Daniel A Stariolo
1Departamento de Física Teórica, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, 20550-013 Rio de Janeiro, Brazil.
Summary
We found that a nematic phase in frustrated spin systems exists when interactions decay as 1/r(α) with 0<α<4. The nematic critical temperature increases with interaction range, peaking near α=0.5.
Area of Science:
- Condensed Matter Physics
- Statistical Mechanics
- Materials Science
Background:
- Frustrated interaction systems exhibit complex orientational order.
- Competing short-range ferromagnetic and long-range antiferromagnetic interactions are key.
- Understanding phase transitions is crucial for predicting material properties.
Purpose of the Study:
- Investigate orientational order in frustrated spin systems.
- Determine the conditions for nematic phase formation.
- Analyze the impact of interaction range on phase transitions.
Main Methods:
- Spin model Hamiltonian with power-law decaying interactions (1/r(α)).
- Self-consistent mean-field calculations for the nematic order parameter.
- Analytical computation of critical temperature and effective Hamiltonian.
Main Results:
- Nematic phase exists for 0<α<4 at the mean-field level.
- Nematic critical temperature increases with interaction range, maximizing near α=0.5.
- Long-wavelength fluctuations are governed by wave vectors k(0)(α) that vanish as α approaches 4.
Conclusions:
- The range of competing interactions fundamentally dictates orientational order.
- A nematic phase is a robust feature in these frustrated systems within a specific interaction range.
- The study provides a theoretical framework for understanding complex magnetic phases.
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