Spin Dynamics in S = 1\20442 Frustrated Spin Dimer Compound K2Co2(SeO3)3

The quantum spin liquid (QSL) state, which has no conventional symmetry-breaking order parameter, can emerge in insulators containing localized spin degrees of freedom. A hallmark of a QSL state is fractionalized spin excitations that can be revealed by a continuum of inelastic neutron scattering. Recently, triangular lattices of 3d7 Co2+ ions and dimers were reported in K2Co(SeO3)2 and K2Co2(SeO3)3, respectively. Neither compound orders magnetically down to 0.3 K. A comparative with inelastic neutron scattering could provide unique insights into the possibility of QSL physics on the triangular lattice for Co2+ ions and dimers respectively. We propose to perform an inelastic neutron scattering experiment on LET to determine the nature of the low-temperature magnetic excitations in K2Co2(SeO3)3 in its distinct phases that can be accessed through the application of a magnetic field.

量子自旋液体（quantum spin liquid, QSL）态不存在常规的对称性破缺序参量，可在带有局域自旋自由度的绝缘体中涌现。QSL态的标志性特征之一为分数化自旋激发，这类激发可通过非弹性中子散射的连续谱予以观测。近期研究分别在K₂Co(SeO₃)₂与K₂Co₂(SeO₃)₃中发现了带有3d⁷构型Co²+离子的三角晶格与自旋二聚体结构。这两种化合物在低至0.3 K的温度下均未出现磁有序。通过非弹性中子散射对比研究，可分别针对Co²+离子三角晶格与自旋二聚体体系，为其量子自旋液体物理特性的存在可能性提供独到见解。我们提议在LET中子谱仪上开展非弹性中子散射实验，以探明K₂Co₂(SeO₃)₃在通过施加磁场可获得的不同物相中的低温磁激发本质。