Spin dynamics in a frustrated magnet with short-range order.
Spin dynamics in a frustrated magnet with short-range order.
复制标题
短程有序受挫磁体中的自旋动力学。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
Bruder
中科院分区：
文献类型：
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作者：
Milá;Poilblanc;Bruder
We analyze the stability of Neel and collinear orders for the frustrated {ital J}{sub 1}-{ital J}{sub 2} model on a square lattice as a function of {ital S} and {ital J}{sub 2}/{ital J}{sub 1} within the Schwinger-boson mean-field theory. For Neel order and {ital finite} {ital S}, the domain of stability extends beyond the classical boundary {ital J}{sub 2}/{ital J}{sub 1}=1/2, suggesting the possibility of stabilizing (with the help of quantum fluctuations) a state that is classically forbidden. We use the solution with short-range Neel order as an effective model for the magnetic properties of high-{ital T}{sub {ital c}} Cu oxides. Predictions are made for the static susceptibility, the dynamical structure factor, and the nuclear relaxation rates (all observable experimentally) at all temperatures. We show that the spin waves are overdamped even at low {ital T} and that a gap opens in the spin-fluctuation spectrum. The susceptibility is nearly linear on a wide intermediate temperature range and obeys a Curie law at high temperature in agreement with 1/{ital N} fermionic expansion.
We analyze the stability of Neel and collinear orders for the frustrated {ital J}{sub 1}-{ital J}{sub 2} model on a square lattice as a function of {ital S} and {ital J}{sub 2}/{ital J}{sub 1} within the Schwinger-boson mean-field theory. For Neel order and {ital finite} {ital S}, the domain of stability extends beyond the classical boundary {ital J}{sub 2}/{ital J}{sub 1}=1/2, suggesting the possibility of stabilizing (with the help of quantum fluctuations) a state that is classically forbidden. We use the solution with short-range Neel order as an effective model for the magnetic properties of high-{ital T}{sub {ital c}} Cu oxides. Predictions are made for the static susceptibility, the dynamical structure factor, and the nuclear relaxation rates (all observable experimentally) at all temperatures. We show that the spin waves are overdamped even at low {ital T} and that a gap opens in the spin-fluctuation spectrum. The susceptibility is nearly linear on a wide intermediate temperature range and obeys a Curie law at high temperature in agreement with 1/{ital N} fermionic expansion.