Spin correlation functions in random-exchange {ital s}=1/2 {ital XXZ} chains

Journal Article · Mon Apr 01 04:00:00 EST 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.361687· OSTI ID:280003

Roeder, H; Stolze, J ^[1]; Silver, R N ^[2]; Mueller, G ^[3]

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1. Physikalisches Institut, Universitaet Bayreuth, 95440 Bayreuth (Germany)
2. Theoretical Division, LANL, Los Alamos, New Mexico 87545 (United States)
3. 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--
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANTIFERROMAGNETISM
CORRELATION FUNCTIONS
CRYSTAL MODELS
EXCHANGE INTERACTIONS
ONE-DIMENSIONAL CALCULATIONS
RANDOMNESS
SPIN ORIENTATION
SPIN SYSTEMS