Optical study of quantum materials

该提案是对量子材料的基础研究，这些材料的性质无法用我们目前的物理和化学知识来解释。如果我们了解这些材料是如何工作的，我们就能更好地利用它们奇异而奇妙的特性。提出了四个项目。它们都涉及红外辐射作为探测器的应用，第一个是我们最近发现，广泛接受的低温下金属电阻与频率相关的模型--朗道费米液体理论--被打破了。我们发现，该理论失败的所有情况下，这种依赖性已被测量，并希望进一步测试。我们的工作已被高影响力杂志PNAS接受。第二个项目是寻找一种新的物质状态，即Dirac-Weyl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。它们似乎具有所需的性质：它们既不是金属，也不是绝缘体，而是具有介于两者之间的奇怪性质，即在零频率处的能隙，这是拓扑学的结果。第三个项目涉及我们继续使用红外线在新材料中研究高温超导性。我们将使用我们的高磁场设备来寻找预测在高磁场下存在的自旋密度波态。将其他项目联系在一起的第四个项目是改进红外技术，使我们保持在该领域的最前沿。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，伦敦安大略的Sciencetech公司，部分由我们小组的毕业生创立，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。欧空局用它来校准普朗克卫星，该卫星是为了测量大爆炸的微波背景辐射而发射的。

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.