IMSE Seminar with Thang Pham on Deciphering Quantum Phenomena in Complex Van der Waals Materials

Different classes of quantum materials abound with rich correlated physics in the bulk form, such as superconductivity, magnetism and more recently, topological states; but many of them are virtually unexplored in the reduced-dimension structures. Specific classes of nanostructured quantum materials of great interest are two-dimensional van der Waals (vdW) magnet and atomically thin single chains of one-dimensional vdW materials. In the first part of my talk, I will introduce an environmentally stable 2D vdW magnet, CrSBr, which allows us to explore its atomic structure by scanning transmission electron microscopy (S/TEM). I will then present an electron-beam irradiation method to manipulate the defect formation and consequently to design the spin texture in the material. In the second part of my talk, I will present my recent efforts in isolation and study of a single chain of 1D vdW materials encapsulated within carbon and boron nitride nanotubes, by the combination of aberration-corrected S/TEM and density functional theory, exemplified by the discovery of torsional instability and helical structural wave in few-to-single chain of charge-density wave NbSe₃.

 

Dr. Thang Pham is a Postdoc Fellow in the Superconducting Quantum Materials and System (SQMS) at Northwestern University. He obtained his Master and PhD degree in Materials Science and Engineering from the University of California at Berkeley in 2018. He then did his postdoctoral study in DMSE at Massachusetts Institute of Technology from 2019-2022. His research is at the interface of discovery of quantum materials and advanced electron microscopy characterization. His research and teaching were recognized by the R&D Awards 2015 and the Outstanding Graduate Student Instructor award from UC Berkeley in 2015.