Resonance structure of dynamic fractional Stark ladders in laser-driven biased superlattices

• Published in: Solid state communications 2011-03, Vol.151 (5), p.392-395
• Main Authors: Karasawa, Tomohiro, Maeshima, Nobuya, Hino, Ken-ichi
• Format: Article
• Language: English
• Subjects: A. Quantum wells; A. Semiconductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Superlattices
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2010.12.011

The resonance structure of an electronic Floquet state in a dynamic fractional Stark ladder (DFSL) is examined based on the scattering theory applied to a dressed potential resulting from renormalization of a laser–electron interaction to an original potential. Here, the DFSL is realized in laser-driven biased superlattices with a fractional matching ratio of a Bloch frequency to a laser frequency. It is revealed that, in contrast to a conventional understanding, the DFSL resonance position and lifetime tend to redshift and shorten, respectively, with an increase in strength of the laser field, and further, these show irregular changes in a limited region of the strength. The underlying physics is discussed in detail. ► Resonance structures of a dynamic fractional Stark ladder are examined. ► Redshift of a resonance position and reduction of a lifetime are found. ► These results are due to ac-Zener tunneling.