High pressure investigation of charge density wave ordering in antiferromagnetic GdNiC2

The family of RNiC2 presents a diversity of electronic ground states, including charge density waves (CDW), magnetic ordering and superconductivity. The characteristics of the charge and magnetic ordering, as well as the interrelation of the two, changes significantly upon replacing the rare earth element, an observation partially attributed to chemical pressure effects. In our recent x-ray diffraction (XRD) experiment we have used hydrostatic pressure (HP) as an alternative tuning parameter of the CDW ordering and its interplay with magnetism. This experiment was focused on ferromagnetic SmNiC2 and has revealed a rich (P,T) phase diagram. Here, we propose to extend our HP XRD study to the antiferromagnetic GdNiC2. The aims of the experiment will be to investigate how does the landscape of the CDW instabilities change when a different type of magnetic ordering sets in and how generic is the (P,T) phase diagram and the newly discovered incommensurate CDW to the RNiC2 family.

RNiC₂系列化合物展现出丰富多样的电子基态，涵盖电荷密度波（charge density waves, CDW）、磁有序与超导性。其电荷与磁有序的特征，以及二者间的相互关联，会随稀土元素的替换发生显著改变，这一观测结果在一定程度上可归因于化学压力效应。在我们近期的X射线衍射（x-ray diffraction, XRD）实验中，我们采用静水压（hydrostatic pressure, HP）作为调控电荷密度波有序及其与磁相互作用的备选参数。该实验聚焦于铁磁性SmNiC₂，且揭示了一套丰富的（P,T）相图。在此，我们提议将静水压X射线衍射研究拓展至反铁磁性GdNiC₂。本实验的目标为探究：当出现不同类型的磁有序时，电荷密度波不稳定性的分布格局会发生何种变化，以及（P,T）相图与此次新发现的非公度CDW对于RNiC₂系列化合物而言具有多大的普适性。