Bloch oscillations in two-dimensional lattices

Bloch oscillations in a two-dimensional periodic potential under a ( relatively weak) static force are studied for separable and non-separable potentials. The dynamics depends sensitively on the direction of the static field with respect to the lattice. Almost dispersionless periodic motion of the wavepackets is observed, as well as breathing modes. The origin of the weak dispersion is analysed. In addition, the coherent Bloch-Zener oscillation for a double-period potential inducing an additional Rowland ghost gap is discussed.