Low-Temperature Ultrahigh Vacuum Scanning Probe Microscope (LT-UHV-SPM)

Center: Schematics of the vacuum system. Around, clockwise from the upper right: (1) Picture of the microscope, (2) graduate student Mehmet Baykara operates the microscope from the control room, (3) graduate student Boris Albers explains our research to NEC chairman Dr. Hajime Sasaki, who visited our lab in October 2006, (4) tip holder with tuning fork and tip (see inset), (5) photograph of the system.

The Yale LT-UHV-SPM system features a three-chamber ultrahigh vacuum system. Chamber 1 is for sample preparation. A combined LEED/Auger system operated in chamber 2 enables to check the crystallinity and cleanliness of surfaces. Finally, chamber 3 houses the home-build scanning probe microscope, which is based on a tuning fork sensor and can be operated simultaneously in noncontact atomic force microscope (NC-AFM) and scanning tunneling microscope (STM) mode. An on-top bath cryostat allows the cooling of the entire microscope to liquid helium temperature. To achieve the low vibration levels necessary for high-resolution scanning probe spectroscopy measurements, which require long data acquisition times, the whole system is placed within a soundproofed room located on a specially reinforced basement slab inside the newly built Malone Engineering Cetner. It is damped by active vibration isolation; operators and control electronics are placed in an adjacent room. For details of the experimental setup, please refer to our respective publication (B. Albers et al., Rev. Sci. Instrum. 79, 033704 (2008)).