High-scan-range cryogenic scanning probe microscope

We have designed and constructed a scanning probe microscope operable at te mperatures down to 260 mK within a top-loading helium-3 cryostat. It achiev es a large scan range with the sample situated near the bottom of the scann ing head-maximizing the cooling efficiency of the liquid helium. The scan h ead is completely thermally compensated, thus eliminating thermal expansion and contraction on cooling and warm-up, as well as thermal drift during op eration. We demonstrate the performance using two distinct scanning probe m ethods: scanning tunneling microscopy and charge accumulation imaging. (C) 2000 American Institute of Physics. [S0034-6748(00)03011-2].