Exploration and quantum tranport study of topological quantum materials

我们的工作旨在寻找和表征的新类别的磁铁与非共面排序，这可能有应用在搜索拓扑保护的电子表面模式。在六方晶系的Gd3Ru4Al12和Gd2PdSi3中，我们发现或帮助发现了大块中心对称磁体中skyrmion晶格相的第一个例子。与以前的工作相比，这些表现出新的现象，由于手性（左手或右手）相互作用的情况下。在Dy3Ru4Al12中，我们发现了一种新形式的倾斜反铁磁体，其中由传导电子介导的磁各向异性和交换相互作用诱导了基于三重自旋的非常规的非共面有序。在所有这些情况下，大的输运响应，如拓扑霍尔和能斯特效应，结果从磁有序，并观察到我们。我们工作的技术方面包括基于对称性原理的材料搜索，使用固态技术（包括固溶体）生长大单晶，使用X射线技术表征这些晶体，以及通过批量热力学和传输测量。

Our work aims at the search for and characterization of new classes of magnets with noncoplanar ordering, which may have applications in the search for topologically protected electronic surface modes. These are sought after for low-loss electronics and for potential applications in quantum computation.In the hexagonal systems Gd3Ru4Al12 and Gd2PdSi3, we discovered or helped to discover the first examples of skyrmion lattice phases in bulk centrosymmetric magnets. As compared to previous work, these show new phenomenology due to the absence of chiral (left- or right-handed) interactions. In Dy3Ru4Al12, we found a new form of canted antiferromagnet, where magnetic anisotropy and exchange interactions mediated by the conduction electrons induce an unconventional, noncoplanar order based on triads of spins. In all these cases, large transport responses, such as topological Hall and Nernst effects, result from the magnetic ordering and were observed by us. Technical aspects of our work included material search based on symmetry principles, growth of large single crystals using solid state techniques (including solid solutions), characterization of these crystals using x-ray techniques, as well as through bulk thermodynamic and transport measurements.