Optical study of quantum materials

这个提案是针对量子材料的基础研究，这些材料的性质是我们目前的物理和化学知识无法解释的。如果我们了解了这些材料是如何工作的，我们就能更好地利用它们奇怪而奇妙的特性。提出了四个项目。它们都使用红外辐射作为探针。第一个原因是我们最近发现了被广泛接受的关于低温下金属电阻频率依赖性的模型，即朗道-费米液体理论。我们发现这个理论在所有的情况下都是失败的，当这种依赖性被测量并且想要进一步测试的时候。我们的工作已经被高影响力期刊PNAS接受。第二个项目是寻找一种新的物质状态，狄拉克-魏尔半金属。到目前为止，还没有发现这样的例子，但我们已经找到了一个有希望的嫌疑人：准晶体。它们似乎具有所需要的特性：它们既不是金属也不是绝缘体，但具有奇怪的中间特性，即恰好在零频率处的能量间隙，这是拓扑结构的结果。第三个项目涉及我们在新材料中使用红外继续研究高温超导性。我们将使用我们的高磁场设备来寻找预计在高磁场中存在的自旋密度波态。第四个将其他项目联系在一起的项目是红外技术的改进，以使我们在该领域保持领先地位。我们将尝试在脉冲超高磁场中使用红外光谱。作为我们过去在这一领域表现的一个例子，安大略省伦敦的Sciencetech公司，部分由我的团队的毕业生创建，生产一种红外光谱仪，SPS-300，运往世界各地的客户。我们设计了它，我的学生编写了它的原始操作软件。欧洲航天局用它来校准普朗克卫星，普朗克卫星是用来测量宇宙大爆炸产生的微波背景辐射的。

This proposal is for basic research on quantum materials with properties that cannot be explained with our current knowledge of physics and chemistry. If we understand how these materials work, we will be in a better position to take advantage of their strange and wonderful properties. Four projects are proposed. They all involve the uses infrared radiation as a probe.The first arises from our recent discovery of the breakdown of the widely accepted model for the frequency dependence of the electrical resistance in metals at low temperatures, the Landau Fermi liquid theory. We find that the theory fails in all cases where this dependence has been measured and want to test this further. Our work has been accepted by the high impact journal PNAS. The second project is a search for a new state of matter, the Dirac-Weyl semimetal. So far, no examples of this has been found but we have located a promising suspect: quasicrystals. They seem to have the properties needed: they are neither metals nor insulators but have strange in-between properties, an energy gap exactly at zero frequency, a property that results from topology. The third project involves our continued study of high temperature superconductivity using infrared, in novel materials. We will use our high magnetic field facility to look for the spin density wave state predicted to exist at high fields. The fourth project that ties the others together is an improvement of infrared techniques to keeps us on the forefront in the field. We will attempt to use infrared spectroscopy in pulsed ultra high magnetic fields. As an example of our past performance in this area, Sciencetech in London Ontario, founded by graduates from my group in part, manufactures an infrared spectrometer, the SPS-300, shipped to customers world wide. We designed it and my students wrote its original operating software. ESA used it to calibrate the Planck satellite that was launched to measure the microwave background radiation from the big bang.