Abstract LT-STM

Posted by zoephel at January 5, 2004 02:17 PM

The LT-STM is specially designed for working at atomic scale at low temperature (i.e. to perform atomic / molecular manipulation or local spectroscopy). The STM has a modified Besocke beetle design which ensures its high stability (dz<1pm) and only a small drift.

The STM is thermally isolated. Its temperature can be varied between 6 ... 300 K. The low temperature of the STM freezes the motion of most adsorbates that can be evaporated onto the sample surface either inside or outside the STM.

The surface / adsorbates can be investigated for weeks. No degredation of the sample will be observed as long as the 4K radiation shield that surrounds the STM remains cold.

Due to th design of the cryostat a very low helium consumption is achieved which requires to refill only 4 liters of liquid helium every 48 hours when the STM is at its lowest temperature.

The whole scan unit is digitally controlled. Therefore a precise tip-postioning on any spot of the sample with any tunneling parameter can be made. This can be used to peform local spectroscopic measurements (i.e. I(V), I(Z)) to reveal electronic or vibrational properties of the sample or the interaction between tip and sample as well a different kinds of manipulation techniques.

Any information (I(t), U(t), XYZ(t), dI/dU ...) can also be recorded during the maniulation.

The standard scan range of 1.5µm x 1.5µm x 0.3µm can be adopted to the desired range. The minimum tunneling current is 2pA.

The system provides optical access onto the sample to control the exact position of the tip with the help of a telescope. The sample transfer can also be done at low temperature. A helium cooled manipulator allows you to prepare, analyze and transfer the samples at temperatures down to 20K.

Last modified January 11 2004. Print this.