Innovative experiments on quantum materials

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Quantum materials are at the heart of a very intense research effort worldwide. The reason for this is twofold: on the application side, there is a huge demand for materials with properties such as superconductivity (the possibility to carry current without energy dissipation), particular optical properties (the possibility to absorb certain wavelengths while reflecting others), etc. On the fundamental side, these materials resist concepts and methods developed in the last century to successfully explain the properties of most materials. Understanding the mechanisms responsible for their peculiar properties is a challenge for condensed matter physics: while we know the basic ingredients that correctly describe matter in quantum mechanics, the complexity of their interactions leads to emergent properties that are still difficult to understand. The understanding of these materials is also key to develop devices based on their remarkable properties. Science progresses by confronting theoretical predictions with experimental results. While there is plethora of routinely used experimental techniques, we propose to develop new experiments to probe some of the intriguing properties of quantum materials, thus providing new evidences to progress in their understanding. These experiments, derived from similar experiments we have developed to probe the quantum nature of electricity in circuits, will shed light on the mysterious properties of quantum materials. In a series of original experiments, we will: - Study how topological properties of materials modify their electromagnetic response (longitudinal and transverse) to an incident microwave, possibly at ultra-low temperature and in the presence of a magnetic field. This is critical to the development of electronic devices. - Probe the temperature-dependent scattering time of electrons by measuring the frequency-dependent microwave response of materials showing a universal behavior - the linear dependence of resistivity on temperature. This is essential to validate theories of highly correlated materials. - Measure the way electrons screen an electrostatic field, this giving access to their electronic compressibility. This parameter is key to the understanding of mysterious phases of matter such as the pseudogap one in cuprates. - Observe quantum oscillations at ultra-high field using a time-resolved ac transport measurement in a microsecond pulsed magnetic field. This will help elucidate the mechanism of superconductivity in high Tc superconductors.