Fabrication of robust (bio)interfaces based on reactive polymer films : surface confinement, reactivity and pattern fabrication on multiple length scales

The aim of the work described in this Thesis was to investigate interfacial reactions in confinement on ultrathin homopolymer and diblock copolymer films, the immobilization of (bio)molecules and the fabrication of biomolecular patterns by reactive microcontact printing (µCP) on these reactive polymer films. Taking advantage of the microphase separation of diblock copolymer films, the fabrication of nanopatterns was investigated, which could contribute to the future development of a model system that enables one to area-selectively deposit (write) and address (read out) (bio)molecules

Valley-dependent gauge fields for ultracold atoms in square optical superlattices

We propose an experimental scheme to realize the valley-dependent gauge fields for ultracold fermionic atoms trapped in a state-dependent square optical lattice. Our scheme relies on two sets of Raman laser beams to engineer the hopping between adjacent sites populated by two-component fermionic atoms. One set of Raman beams are used to realize a staggered \pi-flux lattice, where low energy atoms near two inequivalent Dirac points should be described by the Dirac equation for spin-1/2 particles. Another set of laser beams with proper Rabi frequencies are added to further modulate the atomic hopping parameters. The hopping modulation will give rise to effective gauge potentials with opposite signs near the two valleys, mimicking the interesting strain-induced pseudo-gauge fields in graphene. The proposed valley-dependent gauge fields are tunable and provide a new route to realize quantum valley Hall effects and atomic valleytronics.Comment: 5+ pages, 2 figures; language polished, references and discussions added; accepted by PR