Non-haldane spin-liquid models with exact ground states

被引:103
作者
Kolezhuk, AK
Mikeska, HJ
机构
[1] Univ Hannover, Inst Theoret Phys, D-30167 Hannover, Germany
[2] Natl Acad Sci, Inst Magnetism, UA-252142 Kiev, Ukraine
[3] Minist Educ Ukraine, UA-252142 Kiev, Ukraine
关键词
D O I
10.1103/PhysRevLett.80.2709
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
We present a family of spin-ladder models which can be solved exactly for the ground state and exhibit non-Haldane spin-liquid properties as predicted recently by Nersesyan and Tsvelik [Phys. Rev. Lett. 78, 3939 (1997)], and study their excitation spectra using a simple variational Ansatz. The elementary excitation is neither a magnon nor a spinon, but a pair of propagating triplet or singlet solitons connecting two spontaneously dimerized ground states. Second-order phase transitions separate this phase from the Haldane phase and the rung-dimer phase.
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页码:2709 / 2712
页数:4
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