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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.

We present a theoretical study of an electronic state in the semiconductor Wannier-Stark ladder (WSL) driven by an intense THz laser. Numerical calculations based on the R-matrix Floquet theory have revealed that the dynamic localization (DL) is unstable against the Fano resonance-like interminiband decay mechanism caused by the THz-mediated coupling, termed here the dynamic Fano resonance (DFR). The obtained result is sharply contrasted with the conventional understanding without the introduction of DFR that the degree of stability of the DL would be comparable to or more than that of the WSL with no THz laser (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The Langmuir−Blodgett (LB) method was applied to low molecular weight organogelator N-[N-(6-hydroxyhexyl)-3-carbamoylpropyl]-3,4,5-tris(dodecyloxy)benzamide (1) to form molecular-assembly fibers on a solid substrate. Molecule 1 formed a stable monolayer up to 40 mN/m at the air−water interface. The monolayer was transferred onto a mica surface at 35 mN/m. In the transferred film, fibrous structures with typical dimensions of 1.2 nm (height) × 50−100 nm (width) × 5−10 μm (length) were observed by atomic force microscopy. These structures were ordered in specific directions, reflecting the C6 surface crystal symmetry of mica. Lateral modulation frictional force microscope measurements revealed that the fibrous structures had high crystallinity and that the surface groups were hydrophilic. These results enabled us to construct functional fibers by introducing functional units into the hydrophilic part of molecule 1. N-[N-(6-Aminohexyl)-3-carbamoylpropyl]-3,4,5-tris(dodecyloxy)benzamide hydrochloride (2) has ...