A compact dual-tip STM design

A compact dual-tip scanning tunneling microscope (STM) design that achieves both rigidity and stability is presented. We constructed a prototype unit to perform tests in ambient conditions. The two STM tips were able to maintain a stable tunneling condition with the sample surface simultaneously. Topographic images of a fresh cleaved graphite were taken simultaneously from the two tips. A common feature found in both images indicates that the two tunneling spots are /spl sim/800 nm apart.