Intrinsic localized modes and chaos in damped driven rotator lattices.

It is shown that intrinsic localized rotational modes (ILRMs) in parametrically driven damped lattices of coupled classical dipole rotators can become chaotic without losing their localized character. Insight into this behavior is obtained by means of a nonlinear stability analysis. Moreover, we discuss a robust scheme for exploiting a spatially extended chaotic state to generate stationary randomly spaced arrays of driven ILRMs, and show that the associated absorption exhibits unusual signatures.

Observation of a metastable periodic structure for the (001) surface of KTaO3 after cleaving in situ.

Helium atom diffraction experiments carried out under ultrahigh vacuum conditions on a freshly cleaved (001) surface of KTaO3 reveal metastable features which decay over a period of several hours. The initial He diffraction pattern contains large scattering intensity satellite peaks very close to the specular reflection beam. As time from cleaving elapses, the satellite intensities diminish virtually to zero while the specular intensity increases, and the diffraction pattern evolves into one consistent with the (1x1) bulk termination surface.