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K-State Today

December 19, 2017

Twisted bi-layer graphene presented in Physical Review Letters

Submitted by Suprem R. Das

Suprem Das, assistant professor of industrial and manufacturing systems engineering — along with researchers at the U.S. Department of Energy's Ames Laboratory, Iowa State University and Purdue University — has demonstrated that two atomically thin carbon atoms sitting on top of each other, but with a twisting angle between them, can be exploited fundamentally as a testbed to study and manipulate confined infrared plasmon.

Plasmon is a quantum of plasma oscillations, typically observed in metals when shine by electromagnetic radiation. However, in graphene they are treated as special quasi-particles due to the involvement of "Dirac electrons." The underlying physics found in the work could be used as a platform for novel technological platforms.

Das, one of the primary authors in the work, and his colleagues published their findings in a recent issue of Physical Review Letters in a paper titled, "Real-Space Imaging of the Tailored Plasmons in Twisted Bilayer Graphene." Das and Z. Fei originally discussed the idea to pursue an infrared nanoimaging on twisted bilayer graphene to observe the Dirac plasmons that are characterized by the interlayer coupling between two atomic layers of graphene. Such a confinement and unprecedented tuning of plasmons could be used to design new devices such as sensors. Plasmons in single layer graphene is an emerging area with its manipulation possessing potential technological applications such as energy and sensing. Das is interested in exploiting graphene for these novel applications while at K-State. 

Das earned a doctorate in physics from Purdue University. With a year of postdoctoral at Purdue's School of Electrical and Computer Engineering and two and half years of postdoctoral at Iowa State University and Ames Laboratory, he joined K-State as an assistant professor in fall 2017. His research intersects are in the intersection of materials physics, device engineering and manufacturing of graphene, nanotubes and other low-dimensional nanomaterials and devices.