Abstract
Advances in the study of electronic materials have been one of the driving forces for both scientific and technological developments in recent decades, from transistors to quantum devices, from superconductors to topological insulators. Low dimensional systems, such as atomically thin materials and material interfaces, offer a rich ground to discover new types of electronic states for next generation electronic device applications. Spatially resolved electrical probes provide direct access to these states on the mesoscopic scale, complementing conventional transport techniques. In this talk, I will present our recent studies on 2D electronic states employing Microwave Impedance Microscopy (MIM), a scanning probe technique that senses materials’ capacitance and conductivity on the nanoscale. With this technique, we can study nanoscale conductivity variations that help understand the underlying mechanisms of unusual electrical property in many systems. It also enables us to identify new types of electrical phenomena at interfaces and boundaries that would be difficult to access otherwise. Examples include conductivity profiles in 2D topological materials, and a newly discovered domain wall conduction in an antiferromagnetic insulator, Nd2Ir2O7. Such emergent electronic states can potentially be used to achieve new types of applications beyond current capabilities of semiconductor devices.
Biography
Yongtao Cui obtained his PhD degree in Applied Physics from Cornell University in 2011. His PhD study focused on the characterization of magnetic dynamics of a nanomagnet excited by spin transfer torque. He then moved to Stanford University for postdoc research on the development of Microwave Impedance Microscopy and applying it to the study of nanoscale electronic states in quantum materials. He joined the Department of Physics and Astronomy at UC Riverside in 2016. He is also affiliated with the Materials Science and Engineering program at UCR.