  Optically trapped mixed-species single atom arrays with arbitrary geometries
are an attractive and promising platform for various applications, because
tunable quantum systems with multiple components provide extra degrees of
freedom for experimental control. Here, we report the first demonstration of
two-dimensional $6\times4$ dual-species atom assembly with a filling fraction
of 0.88 (0.89) for $^{85}$Rb ($^{87}$Rb) atoms. This mixed-species atomic
synthetic is achieved via rearranging initially randomly distributed atoms
using a sorting algorithm (heuristic heteronuclear algorithm) which is proposed
for bottom-up atom assembly with both user-defined geometries and two-species
atom number ratios. Our fully tunable hybrid-atom system of scalable advantages
is a good starting point for high-fidelity quantum logic, many-body quantum
simulation and forming defect-free single molecule arrays.
