Raman response in antiferromagnetic two-leg S=1/2 Heisenberg ladders

被引:55
作者
Schmidt, KP [1 ]
Knetter, C [1 ]
Uhrig, GS [1 ]
机构
[1] Univ Cologne, Inst Theoret Phys, D-50937 Cologne, Germany
来源
EUROPHYSICS LETTERS | 2001年 / 56卷 / 06期
关键词
D O I
10.1209/epl/i2001-00601-y
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
The Raman response in the antiferromagnetic 2-leg S = 1/2 Heisenberg ladder is calculated for various couplings by continuous unitary transformations. For leg couplings above 80% of the rung coupling a characteristic 2-peak structure occurs with a point of zero intensity within the continuum. Experimental data for CaV2O5 and LayCa14-yCu24O41 are analyzed and the coupling constants are determined. Evidence is found that the Heisenberg model is not sufficient to describe cuprate ladders. We argue that a cyclic exchange term is the appropriate extension.
引用
收藏
页码:877 / 883
页数:7
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