2006/03/31 by Anders W. Sandvik
Chemistry · Physics and Astronomy · #Advanced Condensed Matter Physics #Bilayer #Chemistry #Condensed matter physics #Critical exponent #Critical point (mathematics) #Dimer #Ground state #Membrane #Nuclear magnetic resonance #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Scaling #Theoretical and Computational Physics #cond-mat.dis-nn #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.96.207201
published as Phys. Rev. Lett. 96, 207201 (2006) · 4 pages, 4 figures. v2: minor changes, published version
openalex publication_date 2006/05/22 · arxiv created 2007/07/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The S = 1/2 Heisenberg model is considered on bilayer and single-layer square lattices with couplings J1, J2, with each spin belonging to one J2-coupled dimer. A transition from a Néel to disordered ground state occurs at a critical value of g = J2/J1. The systems are here studied at their dimer-dilution percolation points p*. The multicritical point (g*,p*) previously found for the bilayer is not reproduced for the single layer. Instead, there is a line of critical points (g < g*, p*) with continuously varying exponents. The uniform magnetic susceptibility diverges as T(-alpha) with alpha element of [1/2,1]. This unusual behavior is attributed to an effective free-moment density approximately T(1-alpha). The susceptibility of the bilayer is not divergent but exhibits remarkably robust quantum-critical scaling.