Abstract-Tunable surface plasmon instability leading to emission of radiation

Godfrey Gumbs^1,2, Andrii Iurov^1,3,a), Danhong Huang⁴ and Wei Pan⁵
http://scitation.aip.org/content/aip/journal/jap/118/5/10.1063/1.4927101
1 Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10065, USA
2 Donostia International Physics Center (DIPC), P de Manuel Lardizabal, 4, 20018 San Sebastian, Basque Country, Spain
3 Center for High Technology Materials, University of New Mexico, Albuquerque, New Mexico 87106, USA
4 Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
5 Sandia National Laboratory, Albuquerque, New Mexico 87185, USA
a) Electronic mail: aiurov@chtm.unm.edu
J. Appl. Phys. 118, 054303 (2015); http://dx.doi.org/10.1063/1.4927101

We propose a new approach for energy conversion from a dc electric field to tunable terahertz emission based on hybrid semiconductors by combining two-dimensional (2D) crystalline layers and a thick conducting material with possible applications for chemical analysis, security scanning, medical (single-molecule) imaging, and telecommunications. The hybrid nano-structure may consist of a single or pair of sheets of graphene, silicene, or a 2D electron gas.When an electric current is passed through a 2D layer, we discover that two low-energy plasmon branches exhibit a characteristic loop in their dispersion before they merge into an unstable region beyond a critical wave vector qc . This finite qc gives rise to a wavenumber cutoff in the emission dispersion of the surface plasmon induced instability and emission of radiation(spiler). However, there is no instability for a single driven layer far from the conductor, and theinstability of an isolated pair of 2D layers occurs without a wavenumber cutoff. The wavenumber cutoff is found to depend on the conductor electron density, layer separation, distances of layers from the conductor surface, and the driving-current strength.