近日，英国剑桥大学Castelnovo, Claudio团队研究了掺杂受抑Mott绝缘体稀释极限下的共振价键自旋液体。2025年5月29日出版的《自然—物理学》杂志发表了这项成果。

关于共振价键液体和自旋电荷分离的想法导致了物理学中的关键概念，如量子自旋液体、涌现规范对称性、拓扑序和分数化。尽管在最初推动这一概念的Hubbard模型中，人们做出了大量努力来证明共振价键相的存在，但尚未实现明确的认识。 

研究组通过揭示现实哈密顿量中表现出自旋电荷分离的共振价键相，为这个长期存在的问题提供了一个解决方案。分析表明，在没有交换相互作用的情况下，这种基态出现在具有受抑跳跃的角共享四面体晶格上的半填充Mott绝缘体的稀释掺杂极限中。

研究组在数值上证实，结果扩展到有限交换相互作用、有限尺寸系统和有限掺杂剂密度。尽管人们对几何受挫相互作用中非常规态的出现给予了很多关注，但该工作表明，掺杂莫特绝缘体中的动能受挫可能对稳定真实材料中稳健的拓扑有序态至关重要。

附：英文原文

Title: A resonant valence bond spin liquid in the dilute limit of doped frustrated Mott insulators

Author: Glittum, Cecilie, trkalj, Antonio, Prabhakaran, Dharmalingam, Goddard, Paul A., Batista, Cristian D., Castelnovo, Claudio

Issue&Volume: 2025-05-29

Abstract: Ideas about resonant valence bond liquids and spin–charge separation have led to key concepts in physics such as quantum spin liquids, emergent gauge symmetries, topological order and fractionalization. Despite extensive efforts to demonstrate the existence of a resonant valence bond phase in the Hubbard model that originally motivated the concept, a definitive realization has yet to be achieved. Here we present a solution to this long-standing problem by uncovering a resonant valence bond phase exhibiting spin–charge separation in realistic Hamiltonians. We show analytically that this ground state emerges in the dilute-doping limit of a half-filled Mott insulator on corner-sharing tetrahedral lattices with frustrated hopping, in the absence of exchange interactions. We confirm numerically that the results extend to finite exchange interactions, finite-sized systems and finite dopant density. Although much attention has been devoted to the emergence of unconventional states from geometrically frustrated interactions, our work demonstrates that kinetic energy frustration in doped Mott insulators may be essential for stabilizing robust, topologically ordered states in real materials.

DOI: 10.1038/s41567-025-02923-8

Source: https://www.nature.com/articles/s41567-025-02923-8