TY - JOUR

T1 - Ground-state energy density, susceptibility, and Wilson ratio of a two-dimensional disordered quantum spin system

AU - Peng, J. H.

AU - Tan, D. R.

AU - Jiang, F. J.

N1 - Funding Information:
This study is partially supported by Ministry of Science and Technology of Taiwan.
Publisher Copyright:
© 2020 American Physical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/12/21

Y1 - 2020/12/21

N2 - A two-dimensional (2D) spin-1/2 antiferromagnetic Heisenberg model with a specific kind of quenched disorder is investigated, using the first-principles nonperturbative quantum Monte Carlo calculations (QMCs). The employed disorder distribution has a tunable parameter p which can be considered as a measure of randomness (p=0 correponds to the clean model). Through large-scale QMCs, the dynamic critical exponents z, the ground-state energy densities E0, and the Wilson ratios W of various p are determined with high precision. Interestingly, we find that the p dependencies of z and W are likely to be complementary to each other. For instance, while the z values of 0.4=p=0.9 match well among themselves and are statistically different from that of p=0, the W values for p<0.7 are in reasonably good agreement with W~0.1243 of the clean case. Surprisingly, our study indicates that a threshold of randomness, pW, associated with W exists. In particular, beyond this threshold the magnitude of W grows with p. This is somehow counterintuitive since one expects the spin correlations should diminish accordingly. Similarly, there is a threshold pz related to z after which a constant value is obtained for z. The results presented here are not only interesting from a theoretical perspective but also can serve as benchmarks for future related studies.

AB - A two-dimensional (2D) spin-1/2 antiferromagnetic Heisenberg model with a specific kind of quenched disorder is investigated, using the first-principles nonperturbative quantum Monte Carlo calculations (QMCs). The employed disorder distribution has a tunable parameter p which can be considered as a measure of randomness (p=0 correponds to the clean model). Through large-scale QMCs, the dynamic critical exponents z, the ground-state energy densities E0, and the Wilson ratios W of various p are determined with high precision. Interestingly, we find that the p dependencies of z and W are likely to be complementary to each other. For instance, while the z values of 0.4=p=0.9 match well among themselves and are statistically different from that of p=0, the W values for p<0.7 are in reasonably good agreement with W~0.1243 of the clean case. Surprisingly, our study indicates that a threshold of randomness, pW, associated with W exists. In particular, beyond this threshold the magnitude of W grows with p. This is somehow counterintuitive since one expects the spin correlations should diminish accordingly. Similarly, there is a threshold pz related to z after which a constant value is obtained for z. The results presented here are not only interesting from a theoretical perspective but also can serve as benchmarks for future related studies.

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U2 - 10.1103/PhysRevB.102.214206

DO - 10.1103/PhysRevB.102.214206

M3 - Article

AN - SCOPUS:85098551046

VL - 102

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 21

M1 - 214206

ER -