Study of possible quantum chains in Nd2Zr2O7 in high [110] fields

Nd2Zr2O7 is a new candidate prominent to quantum spin ice proposed theoretically. It has a well-isolated dipolar-octupolar doublet with Ising anisotropy as the crystal field ground state of the Nd3+ ion and the long range “all-in/all-out” magnetic order as the collective ground state. Our previous elastic neutron scattering experiments indicate that in high (110) fields, Nd2Zr2O7 is completely separated into orthogonal sets of chains due to the cancellation of frustrated interactions, resulting in disorder and isolated quantum spin-1/2 XYZ chains. We propose to use inelastic neutron scattering to verify this scenario and investigate the possible spinon excitations.

Nd₂Zr₂O₇是理论上提出的极具潜力的量子自旋冰（quantum spin ice）新型候选材料。其Nd³+离子的晶体场基态（crystal field ground state）为具备伊辛各向异性（Ising anisotropy）的高度孤立偶极-八极双重态（dipolar-octupolar doublet），体系的集体基态则呈现长程“全入/全出”磁有序。我们此前的弹性中子散射（elastic neutron scattering）实验表明，在沿(110)方向的强磁场中，Nd₂Zr₂O₇因阻挫相互作用（frustrated interactions）被完全抵消，彻底拆分为正交的链状集合，进而形成无序态与孤立的量子自旋1/2 XYZ链。本研究拟采用非弹性中子散射（inelastic neutron scattering）实验验证该物理图像，并对可能存在的自旋子激发（spinon excitations）展开探究。