Dual thermal pseudocritical features in a spin-1/2 Ising chain with twin-diamond geometry

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Magnetism

Background:

• Investigates the magnetic structure of Cu_{2}(TeO_{3})_{2}Br_{2}.
• Focuses on decorated one-dimensional Ising models.

Purpose of the Study:

• To provide a full thermodynamic description of the coupled twin-diamond chain.
• To explore the ground-state properties and low-temperature behavior.
• To understand the impact of frustration and competing configurations.

Main Methods:

• Exact mapping to an effective Ising chain.
• Compact transfer-matrix formulation.
• Ground-state analysis and analysis of thermodynamic properties.

Main Results:

• Identified five distinct ground states, including two with extensive degeneracy (frustrated sectors).
• Observed characteristic entropy plateaus separating ordered phases.
• Demonstrated sharp yet continuous variations in thermodynamic quantities, indicating pseudotransition behavior.

Conclusions:

• The coupled twin-diamond chain is an exactly solvable model.
• Internal frustration and competing configurations lead to dual pseudocritical features in one dimension.
• Provides insights into systems with complex magnetic structures and frustration.