Scanning Microwave Microscopy Study of Complex Quantum Matter

Stanford University, Stanford CA

Investigators

Abstract

Technical Abstract The goal of this NSF program is to study the local electromagnetic properties of strongly interacting electron systems using scanning microwave impedance microscopy. These materials have inherent tendency towards inhomogentiy, making local study highly informative and necessary. Near-field microwave impedance microscopy (MIM) is a novel technique to address this problem. The local dielectric response to electromagnetic waves represents the collective behavior of the electronic system and measures the two-particle correlation functions, complementary to the information obtained by tools sensitive to single particle behavior such as STM. A novel cryogenic variable-temperature (2-300K) MIM equipped with a 9T magnet has been developed and will be used for this study. The combined strength of high resolution microwave imaging (currently at 100 nm, with a plan to further improve) and low-T/high-B environment will enable the visualization of many interesting physical processes, such as metal-insulator transition, phase changing process, regional superconductivity, and multiferroics. Because of the relative ease of operation, the experience of nanoscale electrical imaging is also of pedagogical importance to the undergraduate, graduate students and postdoc in the project. Non-Technical Abstract The goal of this NSF program is to study the local electromagnetic properties of strongly interacting electron systems using scanning microwave impedance microscopy. These materials have great technological potential but are not well understood largely due to inherent tendency towards inhomogentiy, making local study highly informative and necessary. A novel cryogenic variable-temperature (2-300K) near-field microwave impedance microscope equipped with a 9Tesla magnet has been developed and will be used for this study. The combined strength of high resolution microwave imaging and low-T/high-B environment will enable insights not possible to obtain by other means. This tool will be very useful for other fields and for education. Because of the relative ease of operation, the experience of nanoscale electrical imaging is also of pedagogical importance to the undergraduate, graduate students and postdoc in the project.