Synthesis and Advanced Characterization of Quantum Materials

这项提案寻求对我的量子材料实验研究项目的支持。这些材料对于它们未来的应用非常重要，因为它们通常不是传统理论所描述的。这些系统包括高温超导体，包括新发现的磁石，低维和几何受阻的磁体，以及具有拓扑秩序的材料。 我的研究项目本质上是高度协作和跨学科的，在研究的所有阶段都有国际顶尖科学家以及研究生和本科生参与。作为这项研究的直接结果，我们将发现并表征具有各种奇异基态的磁性系统，包括量子和经典量子自旋、冰和液体。我们将确定可能的时间反转对称超导态，并对新发现的超导体的基本性质进行详细研究。 要研究的磁性体系包括焦绿石铁虹酸盐，它结合了强烈的自旋-轨道耦合和具有几何受挫的拓扑有序。我们将合成其他焦绿石，如Tb2GeO7，Yb2GeO7，Ho2Ge2O7，Pr2Pb2O7和Nd2Pb2O7，然后利用内部和国际用户设备进行介子自旋驰豫、中子散射、磁化和其他研究，以确定各种新的磁性基态。我们将合成其他具有几何受挫的系统，包括尖晶石BaHo2O4和FeV2O4，寻找奇异的基态和新的突然出现的自旋激发。 我们将对掺杂的拓扑绝缘体CuxBi2Se3和其他潜在的拓扑超导体进行详细的Muon自旋驰豫/旋转研究，以寻找拓扑超导态的证据。我们将继续研究已被确认为手性p波拓扑超导体的Sr2RuO4，使用？？核磁共振来寻找样品表面附近的特征边缘电流。 我们将继续努力全面了解URu2Si2的电子和磁性状态。我们将使用化学替代将系统驱动到量子临界点，使用介子和中子和体相结合的技术来研究这种演化。 我的研究计划正处于一个令人兴奋的时刻，新的实验设备目前正在上线，在不久的将来。这些措施包括在TRIUMF上具有增强能力的新的Muon光束线，由于开发了额外的驱动器加速器而大大增加了？核磁共振的波束时间，以及开发了用于？？核磁共振的超低温(T&lt；0.5K)光谱仪。2013年底，我的实验室将安装一台新的具有3He能力(T&lt；0.5K)的SQUID磁强计。 拟议的研究将涉及广泛的实验技术，首先是利用光学成像和三弧熔炉进行材料合成。我们将使用我们的新型低温SQUID磁强计测量低至0.5K的磁化率(这是加拿大独有的功能)。我们将使用强磁场和流体静压的极端条件来扰动系统。我们将使用常规的和低能的介子自旋弛豫/旋转和？核磁共振来测量块体和薄膜样品中的局域真实空间磁行为。最后，我和我的学生将与领导小组合作，使用各种实验技术进行研究，包括扫描隧道显微镜、中子散射和角度分辨光电子能谱。

This proposal seeks support for my research program in the experimental study of Quantum Materials. These materials are important both for their future use in applications and because they are often not described by traditional theories. Such systems include high temperature superconductors including the newly discovered pnictides, low dimensional and geometrically frustrated magnets and materials with topological order. My research program is highly collaborative and interdisciplinary in nature, involving international leading scientists and both graduate and undergraduate students in all stages of the research. As a direct result of this research we will discover and characterize magnetic systems with a variety of exotic ground states including both quantum and classical quantum spin ices and liquids. We will identify possible broken time reversal symmetry superconducting states and perform detailed studies of the fundamental properties of newly discovered superconductors. Magnetic systems to be studied include pyrochlore iridates which combine strong spin-orbit coupling and topological order with geometrical frustration. We will synthesize other pyrochlores such as Tb2GeO7, Yb2GeO7, Ho2Ge2O7, Pr2Pb2O7 and Nd2Pb2O7 then perform muon spin relaxation, neutron scattering, magnetization and other studies using both in-house and international user facilities to identify a variety of novel magnetic ground states. We will synthesize other systems with geometrical frustration including the spinels BaHo2O4 and FeV2O4, searching for exotic ground states and novel emergent spin excitations. We will perform detailed muon spin relaxation/rotation studies of the doped topological insulator CuxBi2Se3 and other potential topological superconductors to search for evidence of a topological superconducting state. We will continue our study of Sr2RuO4 which has been identified as a chiral p-wave topological superconductor, using ß-NMR to search for characteristic edge currents near the sample surface. We will continue our efforts to fully understand the electronic and magnetic states of URu2Si2. We will use chemical substitutions to drive the system to a quantum critical point, using muons and neutrons with bulk techniques to study this evolution. My research program is at an exciting juncture with new experimental facilities coming online at present in the imminent future. These include new muon beamlines at TRIUMF with enhanced capabilities, greatly increased beamtime for ß-NMR due to the development of an additional driver accelerator and the development of a very low temperature (T<0.5K) spectrometer for ß-NMR. A new SQUID magnetometer with 3He capability (T<0.5K) will be installed in my laboratory during late 2013. The proposed studies will involve a wide range of experimental techniques, starting with materials synthesis using optical image and tri-arc furnaces. We will measure magnetic susceptibility down to 0.5K using our new low temperature SQUID magnetometer (a unique capability in Canada). We will perturb systems using extreme conditions of high magnetic field and hydrostatic pressure. We will use both conventional and low energy muon spin relaxation/rotation and ß-NMR to measure the local real space magnetic behavior in both bulk and thin film specimens. Finally, my students and I will collaborate with leading groups for studies using a variety of experimental techniques including scanning tunneling microscopy, neutron scattering and angle-resolved photoemission spectroscopy.