Spin correlation functions in random-exchange {ital s}=1/2 {ital XXZ} chains
- Physikalisches Institut, Universitaet Bayreuth, 95440 Bayreuth (Germany)
- Theoretical Division, LANL, Los Alamos, New Mexico 87545 (United States)
- Department of Physics, The University of Rhode Island, Kingston, Rhode Island 02881-0817 (United States)
The decay of (disorder-averaged) static spin correlation functions at {ital T}=0 for the one-dimensional spin-1/2 {ital XXZ} antiferromagnet with uniform longitudinal coupling {ital J}{Delta} and random transverse coupling {ital J}{lambda}{sub {ital i}} is investigated by numerical calculations for ensembles of finite chains. At {Delta}=0 ({ital XX} model) the calculation is based on the Jordan-Wigner mapping to free lattice fermions for chains with up to {ital N}=100 sites. At {Delta}{ne}0 Lanczos diagonalizations are carried out for chains with up to {ital N}=22 sites. The longitudinal correlation function {l_angle}{ital S}{sup {ital z}}{sub 0}{ital S}{sup {ital z}}{sub {ital r}}{r_angle} is found to exhibit a power-law decay with an exponent that varies with {Delta} and, for nonzero {Delta}, also with the width of the {lambda}{sub {ital i}}-distribution. The results for the transverse correlation function {l_angle}{ital S}{sup {ital x}}{sub 0}{ital S}{sup {ital x}}{sub {ital r}}{r_angle} show a crossover from power-law decay to exponential decay as the exchange disorder is turned on. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 280003
- Report Number(s):
- CONF-951101-; ISSN 0021-8979; TRN: 96:021489
- Journal Information:
- Journal of Applied Physics, Vol. 79, Issue 8; Conference: 40. conference on magnetism and magnetic materials, Philadelphia, PA (United States), 6-9 Nov 1995; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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