Quantum disorder in a quasi-2D quantum Heisenberg antiferromagnet

Magnetic order and disorder in a quasi-two-dimensional quantum Heisenberg antiferromagnet with randomized exchange
Phys. Rev. B 102, 174429 (2020)

A team of researchers from the United Kingdom and Slovenia has published a paper in Physical Review B.

The paper co-authored by Matjaž Gomilšek explores the influence of randomized exchange bonds on the magnetism of a S = 1/2 quantum Heisenberg antiferromagnet (QHAF) on a quasi-2D square lattice. The authors find that magnetic order is strongly suppressed by exchange strength randomness (realized by chemical substitution), with an extended quantum-disordered phase forming over a wide range of intermediate substitution levels, where no ground-state magnetic order is observed. The observed critical substitution levels are described by a simple energetics-based model of competing local magnetic orders. Due to the ubiquity of quenched disorder in many of the most interesting QHAF materials, this study should have wide implications in the field of quantum magnetism.

Visualization of 2D random bonds

Random exchange bonds on a 2D square lattice. Blue represents unsubstituted bonds, green once-substituted and red twice-substituted bonds. The probability of single-site substitution increases linearly from left to right. Author Matjaž Gomilšek

Zoomed visualization of 2D random bonds

Zoomed-in random exchange bonds on a 2D square lattice. Author Matjaž Gomilšek