Specifications include, but are not limited to: Key operating capabilities for a Low Temperature STM / Q+ AFM • Sample orientation facing downwards is preferred over sample facing “upwards” because sample facing downwards facilitates in situ line-of-sight deposition during STM experiments from crucibles and with wider range of materials. • The STM pre-amplifier should include integrated capacitive compensation at the first IVconverter to provide optimized modulation spectroscopy for optimal signal to noise performance. Not having this capability limits spectroscopy performance • The pre-amplifier should have a floating IV converter for compensation of electrostatic forces at the tip side (especially critical for Q+ operation.) This compensation is required for high resolution STS with Q+ and, depending on the sample, critical to achieve atomic resolution • A critical capability is the ability to quickly switch between applying the bias capability (and measuring tunneling current) to either the tip or the sample. Not having this quick-change capability significantly limits the capabilities of an instrument. Other important items • Large coarse range for X, Y and Z axis (at room temperatures, 77K, and 5K). The larger the better to help with sample varieties and sample navigation. This is especially relevant for curved single crystal substrates. At least 5 mm for X & Y at 5 K temperatures and 10 mm in Z so that samples up to 6 mm thick are possible. Large (10 mm) Z retraction is also required for in situ deposition to avoid shadowing effects due to the probe tip. • Guaranteed atomic resolution at both 5K AND 77K. • Large scanning range at room temperature and low (77K, 5K temperature). Recommend at least: o 10×10 μm in XY, 1 μm in Z at room temperatures o At least 4×4 μm in XY, 0.4 μm in Z at 77K o Approximately 1.8×1.8 μm in XY, 0.2 μm in Z at 5K • LHe Hold time > 60 hrs