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ECE Colloquium Series – Professor Ke Wang
September 20 @ 3:45 pm - 5:15 pm
As part of the *Eleanore Hale Wilson Lecture Series, ECE is proud to present:
Manipulating Charge Carriers in Gate-defined 2D van der Waals Nanostructures
Professor Ke Wang
University of Minnesota
Host: Professor Tony Low
Since the discovery of graphene via mechanical exfoliation, it has been shown that the electronic properties of solids can undergo dramatic change when the material thickness is reduced to the atomic limit. Recently, the quality of these 2-dimensional (2D) electronic systems has been significantly improved by hexagonal boron nitrides encapsulation, enabling the electron mean free path only limited by the size of the samples. However, mesoscopic transport studies in these systems are relatively unexplored due to the challenges in the device fabrication processes. Here we develop a robust procedure for making gated-defined nanostructures in 2D van der Waals materials without compromising their intrinsic 2DEG quality, providing versatile experimental platforms to explore various novel quantum phenomena in these systems. By confining and manipulating charge carriers , we demonstrate relativistic electron-optics, resonant quantum Hall (QH) tunneling spectroscopy, tunable optical trion lifetime and quantized mesoscopic transport in graphene and transition metal dichalcogenides . Our results bode well for addressing many key problems in condensed matter physics, including Luttinger physics, high fidelity logic gates in Loss-DiVincenzo qubits, gate-controlled quantum optics, measurement of small fractional QH energy gaps, and functional quantum devices based on pseudospin manipulation and electron optics.
 Wang, et al, Phys. Rev. Lett. 111, 046801 (2013).  Wang, et al, Nature Nano. 13, 128–132 (2018).
Ke Wang was born in Chengdu, China. He obtained his undergraduate degree in Physics from University of Science and Technology of China and his Ph.D. in Physics from Princeton University working with Prof. Jason R. Petta. After his post-doctoral research with Prof. Philip Kim at Harvard University, he joined University of Minnesota as an assistant Professor in Physics in 2018. His current research interests include correlated electrons at the quantum limit and transport properties of novel 2D functional materials.
*Established in 2009, the Eleanore Hale Wilson Fund supports engineering field leaders for travel to Minnesota to share their expertise and discoveries with University of Minnesota graduate students, faculty, and alumni. The fund also supports the receptions held in honor of each speaker.