Theory of two-dimensional quantum Heisenberg antiferromagnets with a nearly critical ground state

Journal Article · Sun May 01 00:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.49.11919· OSTI ID:7206591

Chubukov, A V ^[1]; Sachdev, S; Ye, J ^[2]

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1. Departments of Physics and Applied Physics, P.O. Box 208120, Yale University, New Haven, Connecticut 06520-8120 (United States) P. L. Kapitza Institute for Physical Problems, Moscow (Russian Federation)
2. Deparment of Physics and Applied Physics, P.O. Box 208120, Yale University, New Haven, Connecticut 06520-8120 (United States)

We present the general theory of clean, two-dimensional, quantum Heisenberg antiferromagnets which are close to the zero-temperature quantum transition between ground states with and without long-range Neel order. While some of our discussion is more general, the bulk of our theory will be restricted to antiferromagnets in which the Neel order is described by a three-vector order parameter. For Neel-ordered states, nearly critical'' means that the ground-state spin stiffness, [rho][sub [ital s]], satisfies [rho][sub [ital s]][much lt][ital J], where [ital J] is the nearest-neighbor exchange constant, while nearly critical'' quantum-disordered ground states have an energy gap, [Delta], towards excitations with spin 1, which satisfies [Delta][much lt][ital J]. The allowed temperatures, [ital T], are also smaller than [ital J], but [ital no] restrictions are placed on the values of [ital k][sub [ital B]][ital T]/[rho][sub [ital s]] or [ital k][sub [ital B]][ital T]/[Delta]. Under these circumstances, we show that the wave vector and/or frequency-dependent uniform and staggered spin susceptibilities, and the specific heat, are completely universal functions of just three thermodynamic parameters. On the ordered side, these three parameters are [rho][sub [ital s]], the [ital T]=0 spin-wave velocity [ital c], and the ground-state staggered moment [ital N][sub 0]; previous works have noted the universal dependence of the susceptibilities on these three parameters only in the more restricted regime of [ital k][sub [ital B]][ital T][much lt][rho][sub [ital s]]. On the disordered side the three thermodynamic parameters are [Delta], [ital c], and the spin-1 quasiparticle residue [ital scrA]. Explicit results for the universal scaling functions are obtained by a 1/[ital N] expansion on the [ital O]([ital N]) quantum nonlinear [sigma] model, and by Monte Carlo simulations. These calculations lead to a variety of testable predictions..

• OSTI ID: 7206591
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 49:17; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HEISENBERG MODEL
GROUND STATES
HIGH-TC SUPERCONDUCTORS
ANTIFERROMAGNETISM
COMPUTERIZED SIMULATION
CUPRATES
MAGNETIC SUSCEPTIBILITY
MONTE CARLO METHOD
ORDER-DISORDER TRANSFORMATIONS
SPECIFIC HEAT
SPIN WAVES
CALCULATION METHODS
COPPER COMPOUNDS
CRYSTAL MODELS
ENERGY LEVELS
MAGNETIC PROPERTIES
MAGNETISM
MATHEMATICAL MODELS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SIMULATION
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
665411* - Basic Superconductivity Studies- (1992-)