Physics Department Seminar
Dr. Adina Luican-Mayer
Assistant Professor
University of Ottawa
Tuesday, March 26, 2019

Custom low-dimensional material systems explored at the atomic scale

Innovative technologies have a history of capitalizing on the discovery of new physical phenomena, often at the confluence of advances in material characterization techniques and innovations in design and controlled synthesis of high-quality materials. Pioneered by the discovery of graphene, atomically thin materials (2D materials) hold the promise for realizing physical systems with distinct properties, previously inaccessible.

In this talk I will describe experiments that seek to uncover the novel physical phenomena in 2D materials by using scanning tunneling microscopy and spectroscopy (STM/STS). STM allows us to spatially resolve both the local electronic and structural properties of materials down to atomic scale. In particular, I will discuss consequences of twisting graphene layers, which leads to the formation of MoirĂ© patterns and results in a system with extraordinary electronic properties tuned by the twist angle. I will then focus on the 1T polymorph of TaS2, which has one of the richest phase diagrams among the layered transition metal dichalcogenides. Using a combination of scanning probe microscopy, electrical and optical characterization, we address the question of how the transition from bulk to few layers affects the different charge density wave phases in this material. Lastly, I will describe our atomic-scale characterization of the in-plane anisotropic 2D semiconductor ReS2. We demonstrate that rhenium atoms form diamond-shaped clusters, organized in disjointed chains, and characterize the semiconducting electronic band gap by STS.  By spatially mapping the local density of states around defects in ReS2, we explore their origin and electrostatic nature.


Adina Luican-Mayer started as an assistant professor in the Physics Department at uOttawa in January 2016. She received her undergraduate degree from Jacobs University Bremen in Germany (2006) and her PhD in Physics from Rutgers University (2012). Prior to joining uOttawa, she was the Alexei Abrikosov postdoctoral fellow at the Center for Nanoscale Materials at Argonne National Laboratory outside Chicago. Her research group focuses on uncovering the novel electronic properties of low-dimensional systems custom made by stacking atomically thin sheets of van der Waals materials using scanning probe microscopy and supporting spectroscopic techniques.