We present a model as well as experimental results for a surface electrode radio-frequency Paul trap that has a circular electrode geometry well-suited for trapping of single ions and two-dimensional planar ion crystals. The trap design is compatible with microfabrication and offers a simple method by which the height of the trapped ions above the surface may be changed \emph{in situ}. We demonstrate trapping of single and few Sr+ ions over an ion height range of 200-1000 microns for several hours under Doppler laser cooling, and use these to characterize the trap, finding good agreement with our model.
@article{arxiv.1008.1603,
title = {A surface electrode point Paul trap},
author = {Tony Hyun Kim and Peter F. Herskind and Taehyun Kim and Jungsang Kim and Isaac L. Chuang},
journal= {arXiv preprint arXiv:1008.1603},
year = {2011}
}