Random-exchange quantum Heisenberg antiferromagnets on a square lattice
Abstract
The ground state properties of random-exchange spin- (1)/(2) Heisenberg antiferromagnets (AFM) on a square lattice are investigated using a combination of quantum Monte Carlo simulations, exact numerical diagonalizations, and spin wave calculations. Whereas arbirarily weak disorder has a drastic effect on one-dimensional Heisenberg AFM, we find that in two dimensions the characteristics of the ground state such as long-range order is robust even against strong disorder. While the antiferromagnetic order parameter and the spin stiffness are exponentially reduced for singular exchange distributions, they vanish only in the limit of infinite randomness.
- Publication:
-
Physical Review B
- Pub Date:
- February 2006
- DOI:
- 10.1103/PhysRevB.73.060403
- arXiv:
- arXiv:cond-mat/0511306
- Bibcode:
- 2006PhRvB..73f0403L
- Keywords:
-
- 75.40.Mg;
- 75.10.Nr;
- 02.70.Ss;
- 75.30.Ds;
- Numerical simulation studies;
- Spin-glass and other random models;
- Quantum Monte Carlo methods;
- Spin waves;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Disordered Systems and Neural Networks
- E-Print:
- Phys. Rev. B 73, 060403(R) (2006)