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The Effective Theory of Hole Doped Spin-1 Chain

Xi Dai·Bin Chen·Zhao-Bin Su
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Abstract

An effective theory for the hole doped spin-1 antiferromagnetic chain is proposed in this paper. The two branches of low energy quasipaticle excitation is obtained by the diagrammic technique. In the large t limit(in which t is the hole hopping term), the lower band is essentially the bound state of one hole and one magnon and the other band is the sigle hole state. We find a critical value of t, $t_c=0.21Δ_H$(in which $Δ_H$ is the Haldane gap).For $t>t_c$, with the decrement of t, the mixing of these two bands become stronger and stronger, and at the same time the effective band mass becomes larger and larger. When $t<t_c$ the minimum of the lower band moves away from zero the another point between zero and $π/2$. The spin strcture factor is also calculated in this paper, and we find that for large t limit the main contribution is from the inter-band transition which induce a resonant peak in the Haldane gap. While for small t limit the main contribution is from the intra-band transition which only cause a diffusion like broad bump in the Haldan gap.

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Xi Dai, Bin Chen, Zhao-Bin Su. 1999-01-22. The Effective Theory of Hole Doped Spin-1 Chain. https://arxiv.org/abs/cond-mat/9901234

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