Numerical Diagonalization Study of the Phase Boundaries of the S=2 Heisenberg Antiferromagnet on the Orthogonal Dimer Lattice

TL;DR

This study uses numerical diagonalization to analyze phase boundaries in the S=2 Heisenberg antiferromagnet on an orthogonal dimer lattice, revealing how the intermediate phase widens with increasing spin.

Contribution

It provides new insights into the phase diagram of the S=2 case, extending previous smaller-S analyses and highlighting the evolution of phase boundaries with spin magnitude.

Findings

Intermediate phase widens as S increases to 2

Exact dimer and Neel phases are delineated

Numerical diagonalization effectively studies large-spin systems

Abstract

The S=2 Heisenberg antiferromagnet on the orthogonal dimer lattice is studied. The edges of the exact dimer and Neel-ordered phases in the ground state of the system are examined by the numerical diagonalization method. Our present results are discussed by combining them with previously obtained estimates for smaller-S cases. We find that an intermediate region between the exact dimer and Neel-ordered phases gradually widens as spin S is increased up to S=2.