Strong terahertz emission from superlattices via Zener tunnelingPeng Han1, Kui-juan Jin1, B. C. Sanders2, 3, Yueliang Zhou1, Hui-bin Lu1 and Guo-zhen Yang1
1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100080, China
2 Institute for Quantum Information Science, University of Calgary - Calgary, Alberta T2N 1N4, Canada
3 Centre for Quantum Computer Technology, Macquarie University - Sydney, New South Wales 2109, Australia
received 5 February 2007; accepted in final form 4 June 2007; published July 2007
published online 28 June 2007
We develop a comprehensive, elegant theory to explain terahertz (THz) emission from a superlattice over a wide range of applied electric fields, which shows excellent agreement between theory and experiment for a GaAs/Al0.3Ga0.7As superlattice. Specifically we show that increasing the electric field increases THz emission for low fields, then reduces emission for medium fields due to field-induced wave function localization, and then increases emission in the high field due to delocalization and Zener tunneling between minibands. Our theory shows that Zener tunneling resonances yield high THz emission intensities and points to superlattice design improvements.
73.21.Cd - Superlattices.
73.40.-c - Electronic transport in interface structures.
78.47.+p - Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter.
© Europhysics Letters Association 2007