UNDERSTANDING FAR-INFRARED ABSORPTION IN THE S = 1 ANTIFERROMAGNETIC CHAIN COMPOUND NENP

被引:71
作者
MITRA, PP [1 ]
HALPERIN, BI [1 ]
机构
[1] HARVARD UNIV,LYMAN LAB PHYS,CAMBRIDGE,MA 02138
关键词
D O I
10.1103/PhysRevLett.72.912
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Infrared transmission measurements on the S = 1 antiferromagnetic chain compound NENP [Ni(C2H8N2)2NO2ClO4] in applied magnetic fields show a sharp absorption line at the field-shifted Haldane gap. This violates a wave-vector selection rule of the Hamiltonian normally used for NENP, as the gap excitations occur at the Brillouin zone boundary. We argue that the crystal structure admits terms which can explain the absorption lines. The observation of a finite gap at all applied fields can be explained by the presence of an induced staggered magnetic field, originally proposed by Chiba et al.
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页码:912 / 915
页数:4
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