Abstract
We describe the construction and performance of a scanning tunneling microscope capable of taking maps of the tunneling density of states with sub-atomic spatial resolution at dilution refrigerator temperatures and high (14 T) magnetic fields. The fully ultra-high vacuum system features visual access to a two-sample microscope stage at the end of a bottom-loading dilution refrigerator, which facilitates the transfer of in situ prepared tips and samples. The two-sample stage enables location of the best area of the sample under study and extends the experiment lifetime. The successful thermal anchoring of the microscope, described in detail, is confirmed through a base temperature reading of 20 mK, along with a measured electron temperature of 250 mK. Atomically resolved images, along with complementary vibration measurements, are presented to confirm the effectiveness of the vibration isolation scheme in this instrument. Finally, we demonstrate that the microscope is capable of the same level of performance as typical machines with more modest refrigeration by measuring spectroscopic maps at base temperature both at zero field and in an applied magnetic field.
| Original language | English |
|---|---|
| Article number | 103903 |
| Journal | Review of Scientific Instruments |
| Volume | 84 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2013 |
Bibliographical note
Funding Information:We acknowledge key contributions made by Guido van Loon, Steve Shedd, and Peter Heiland from Integrated Dynamics Engineering in the design and construction of the aluminum support structure, Michael Gaevski and George P. Watson from the Micro Nano Fabrication Laboratory at Princeton University in the annealing of the silver rods, Steven Lowe and William Dix from Department of Physics at Princeton University for machining assistance, Jeff Coles, Paul Busby, Adrian Bircher, and Andy Yardy at Oxford Instruments in the design and construction of the cryostat and the dilution refrigerator, and Se-Jong Kahng from Korea University in the design and construction of the STM head. The instrumentation and infrastructure were supported by grants from National Science Foundation (NSF) - DMR1104612, (U.S.) Army Research Office (USARO) Grant Nos. W911NF-1-0262 and W911NF-1-0606, the Linda and Eric Schmidt Transformative Fund, and the W. M. Keck Foundation.