美国莱斯大学Dai, Pengcheng团队研究了烧绿石自旋冰中涌现光子和分馏的中子散射和热力学证据。相关论文发表在2025年6月19日出版的《自然—物理学》杂志上。
角共享四面体的三维烧绿石晶格可以容纳量子自旋冰，这是在其他烧绿石化合物中发现的经典自旋冰的量子类似物。这种状态可以表现为量子自旋液体，事实上，这些化合物被预测具有新兴的规范场，除了存在更高能量的旋子激发外，还会产生接近零能量的线性色散集体磁激发。
研究组对Ce2Zr2O7烧绿石单晶进行了极化中子散射实验。除了在更高能量下自旋的特征外，他们还发现了接近零能量的磁激发的证据。此外，研究组进行了热容测量，发现线性色散无间隙玻色子模的温度依赖性与立方一致。将观测到的磁激发与理论计算进行比较，研究组认为Ce2Zr2O7是具有主要偶极伊辛相互作用的偶极-八极量子自旋冰的有力候选者。
附：英文原文
Title: Neutron scattering and thermodynamic evidence for emergent photons and fractionalization in a pyrochlore spin ice
Author: Gao, Bin, Desrochers, Flix, Tam, David W., Kirschbaum, Diana M., Steffens, Paul, Hiess, Arno, Nguyen, Duy Ha, Su, Yixi, Cheong, Sang-Wook, Paschen, Silke, Kim, Yong Baek, Dai, Pengcheng
Issue&Volume: 2025-06-19
Abstract: The three-dimensional pyrochlore lattice of corner-sharing tetrahedra can host a quantum spin ice, a quantum analogue of the classical spin ice found in other pyrochlore compounds. This state can manifest a quantum spin liquid, and indeed, these compounds are predicted to have emergent gauge fields that produce linearly dispersing collective magnetic excitations near zero energy, in addition to the presence of higher-energy spinon excitations. Here we use polarized neutron scattering experiments on single crystals of the Ce2Zr2O7 pyrochlore. We find evidence for magnetic excitations near zero energy, in addition to signatures of spinons at higher energies. Furthermore, we perform heat capacity measurements and find behaviour consistent with the cubic-in-temperature dependence expected for linearly dispersing gapless bosonic modes. Comparing the observed magnetic excitations with theoretical calculations, we argue that Ce2Zr2O7 is a strong candidate for a dipolar–octupolar quantum spin ice with dominant dipolar Ising interactions.
DOI: 10.1038/s41567-025-02922-9
Source: https://www.nature.com/articles/s41567-025-02922-9