A ScientaOmicron VT-STM XA is UHV coupled to the A-branch endstation, and is available to users either during their beamtime, or afterwards subject to the availability of staff to take the measurements. The instrument is routinely capable of atomic resolution imaging, even when the adjacent preparation or ARPES chambers are in use. In the right circumstances it can offer a powerful complement to an ARPES experiment.

Please note that the VT-XA does not cool the tip, so the instrument will not achieve the stability or energy resolution of an LT-STM instrument.

Typical applications:

  • Lattice size measurements to within <=1%
  • Identifying when multiple domains are contributing to the photoemission spectra
  • Verifying a successful sample preparation when LEED or ARPES is not sufficient
  • STS and dIdV measurements when ≈120meV energy resolution is acceptabl
Coarse positioning range (x/y/z)10 x 10 x 10mm
Fine scan range (x/y/z)12 x 12 x 1.5μm
Cooled tip?No
Maximum sample temperature500K
Minimum sample temperature (LHe)50K (*Requires advanced planning, contact beamline staff if interested)
Minimum sample temperature (LN2)113K
Arbitrary temperature stabilisation?Yes
Lockin amplifierSRS860

Example data

These measurements were taken at room temperature on 7×7 reconstructed Si(111).

An image of Bloch topography at Vgap plus2V
An image of Bloch topography at Vgap minus2V
An image of Bloch dldV at Vgap minus1V
A graph depicting the conductance of normalised dldv