Труды сотрудников института физики

/ S. S. Aplesnin // Phys. Lett. A. - 2003. - Vol. 313, Is. 1-2. - P. 122-125, DOI 10.1016/S0375-9601(03)00689-3. - Cited References: 17 . - ISSN 0375-9601РУБ Physics, Multidisciplinary

Аннотация: The ground state of two-dimensional Heisenberg spin-1/2 antiferromagnet (AF) with the spin-phonon coupling is studied by the quantum Monte Carlo method. The magnetic moment per site, mean-square vibration of ion, phase diagram of AF long range order-quantum spin. liquid are simulated. The spin-phonon coupling is estimated for R2CuO4, R = Gd, Eu. (C) 2003 Elsevier Science B.V. All rights reserved.

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Держатели документа:
LV Kirenskii Inst Phys, Russian Acad Sci, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН
L. V. Kirenskii Institute of Physics, Siberian Br. of Russ. Acad. of Sci., Krasnoyarsk 660036, Russian Federation

Доп.точки доступа:
Аплеснин, Сергей Степанович

/ S. S. Aplesnin // J. Exp. Theor. Phys. - 2003. - Vol. 97, Is. 5. - P. 969-977, DOI 10.1134/1.1633952. - Cited References: 18 . - ISSN 1063-7761РУБ Physics, Multidisciplinary

Аннотация: The ground state of a two-dimensional antiferromagnet having spins S = 1/2 and interacting with acoustic phonons is investigated in the nonadiabatic approximation using the quantum-mechanical Monte Carlo method. The critical parameters of the spin-phonon coupling, corresponding to the formation of bound spin-phonon excitations, crystal symmetry lowering, and the emergence of a gap in the spin excitation spectrum, as well as the antiferromagnet-quantum spin liquid transition, are determined. The orthorhombicity parameter, the sublattice magnetization, the violation of the spherical symmetry of spin-spin correlation functions, and the magnetic moment in Gd2CuO4 and Eu2CuO4 are calculated. (C) 2003 MAIK "Nauka / Interperiodica".

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Держатели документа:
Russian Acad Sci, Siberian Div, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirenskii Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgoivdok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Аплеснин, Сергей Степанович

/ S. S. Aplesnin // Phys. Solid State. - 1999. - Vol. 41, Is. 1. - P. 103-107, DOI 10.1134/1.1130737. - Cited References: 33 . - ISSN 1063-7834РУБ Physics, Condensed Matter

Аннотация: The two-dimensional (2D) Heisenberg model with anisotropic exchange (Delta=1-J(x)/J(z)) and S=1/2 is investigated by the quantum Monte Carlo method. The energy, susceptibility, specific heat, spin-spin correlation functions, and correlation radius are calculated. The sublattice magnetization (sigma) and the Neel temperature of the anisotropic antiferromagnet are logarithmic functions of the exchange anisotropy: 1/sigma + 1 + 0.13(1) ln(1/Delta). Crossover of the static magnetic structural factor as a function of temperature from power-law to exponential occurs for T(c)/J approximate to 0.4. The correlation radius can be approximated by 1/xi =2.05T(1.0(6))/exp(1.0(4)/ T). For La(2)CuO(4) the sublattice magnetization is calculated as sigma=0.45, the exchange is J=(1125=1305) K; for Er(2)CuO(4)J similar to 625 K and the exchange anisotropy Delta similar to 0.003. The temperature dependence of the static structural magnetic factor and the correlation radius above the Neel temperature in these compounds can be explained by the formation of topological excitations (spinons). (C) 1999 American Institute of Physics. [S1063-7834(99)02401-6].

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Держатели документа:
Russian Acad Sci, LV Kirenskii Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН

Доп.точки доступа:
Аплеснин, Сергей Степанович

/ S. S. Aplesnin // Phys. Status Solidi B. - 1998. - Vol. 207, Is. 2. - P. 491-498, DOI 10.1002/(SICI)1521-3951(199806)207:2491::AID-PSSB4913.0.CO;2-G. - Cited References: 24 . - ISSN 0370-1972РУБ Physics, Condensed Matter

Аннотация: The two-dimensional (2D) Heisenberg model (J 0) with anisotropic exchange Delta = 1-J(X)/J(Z) greater than or equal to 0 and with S = 1/2 is studied by the quantum Monte-Carlo method. Energy, susceptibility, specific heat, spin-spin correlation functions, and correlation radius are calculated. The dependence of the Neel temperature T(N)/J = 2/ln(11/Delta) on the exchange anisotropy is determined. The static magnetic factor is very slowly decreased for T/J 0.4. It is assumed to realize topological excitations in the range of these temperatures. The correlation radius of the isotropic Heisenberg model is fitted by the dependence 1/xi = 2.05T(1.0(6))/exp (1.0(4)/T).The temperature behavior of the static structural magnetic factor in La(2)CuO(4) and Er(2)CuO(4) for T T(N) is in agreement with the MC calculations.

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Держатели документа:
LV Kirenskii Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
ИФ СО РАН

Доп.точки доступа:
Аплеснин, Сергей Степанович