NSF Award
1905950
Non-Technical Abstract<br/>Quantum materials are the future of new electronic devices in our increasingly technological world. Superconductors for MRI medical imaging, a mature technology, and qubits for quantum computing, a nascent technology, are two examples of quantum materials that are or will be ubiquitous in our society. This research is part of a large effort to better understand the functional quantum materials used presently so that the next generation of quantum materials can be discovered. This project will focus on superconducting materials, used both in MRI imaging and quantum computing. Advancing experimental techniques that use the highest magnetic fields available in the world, pulsed power systems, and radio frequency systems are some of the technologies that also can advance sectors such as energy, communications, and manufacturing. Finally, the undergraduate, and graduate students who participate in these projects are trained as the next generation of scientists. <br/><br/>Technical Abstract<br/>Understanding quantum mechanical ground states is essential to create the next generation of electronic devices and develop quantum communications. The PI's research is advancing the understanding of quantum systems by making systematic measurements of quasi-two dimensional organic superconductors that show signatures of inhomogeneous superconductivity. This exotic superconducting state, a tunable mixture of a spatially modulated superconducting order parameter and a magnetic lattice of unpaired electrons, was predicted over 50 years ago, and is called the FFLO state. The FFLO state is highly tunable via temperature, the direction and strength of the magnetic field, and pressure. This research continues the core measurements of rf penetration depth using a tunnel diode oscillator and specific heat of organic and pnictide superconductors. The PI also measures the symmetry and wavelength of the charge modulation in the FFLO state and charge density waves using x-rays. To facilitate these experiments the PI is working with the Advanced Photon Source at Argonne National Laboratory (APS) and the National High Magnetic Field Laboratory in Tallahassee and Los Alamos to upgrade access to high magnetic fields at the APS. In organic and pnictide conductors anion or element substitution and moderate pressure make it easy to traverse the temperature-carrier concentration phase diagram that is ubiquitous among superconducting materials. Tuning the system from the density wave insulating state, through superconductivity, and into a metallic state will provide evidence of the quantum critical point thought to be responsible for superconductivity. Understanding the competition between ground states is a central question in quantum materials and the quantum critical point is central to this problem. The combination of measurements, model calculations, and an extensive library of crystal samples will further the goal of understanding the physics of quantum materials.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
