Imaging, single atom contact and single atom manipulations at low temperature using the new ScientaOmicron LT-UHV-4 STM

Abstract

Abstract. The performances of the new ScientaOmicron LT-UHV 4-STM microscope have been certified by a series of state-of-art STM experiments on an Au(1 1 1) surface at 4.3 K. During the STM operation of the 4 STM scanners (independently or in parallel with an inter tip apex front to front distance down to a few tens of nanometers), a ΔZ stability of about 2 pm per STM was demonstrated. With this LT-UHV 4-STM stability, single Au atom manipulation experiments were performed on Au(1 1 1) by recording the pulling, sliding and pushing manipulation signals per scanner. Jump to contact experiments lead to perfectly linear low voltage I-V characteristics on a contacted single Au ad-atom with no need of averaging successive I-V's. Our results show how this new instrument is exactly 4 times a very precise single tip LT-UHV-STM. Two tips surface conductance measurements were performed on Au(1 1 1) using a lock-in technique in a floating sample mode of operation to capture the Au(1 1 1) surface states via two STM tips dI/dV characteristics.

Training for the 1st international nano-car race: the Dresden molecule-vehicle

“…1 is indicative of the a-d possible quadrants location). This is due to the constrain that, for the competition, the STM tips must be mounted perpendicular to the tip holder (and the surface) to recover the same molecular manipulation conditions on the LT-UHV 4-STM instrument than on a single tip LT-UHV-STM [5]. This is imposing that the scanning and racing zone per team be located at the periphery of the Au(1 1 1) surface.…”

“…Each molecule-vehicle is to be driven by an inelastic electronic tunneling current phenomenon, using the tip of a scanning tunneling microscope (STM) at low temperature (LT) and in an ultrahigh vacuum (UHV) environment [2][3][4]. Four nano-cars can be driven in parallel, independently and on the same surface, thanks to the newly installed LT-UHV 4-STM instrument in Toulouse, built by ScientaOmicron and having four STM heads able to operate on the same surface [5].…”

“…That information was used for selecting the six teams accepted to race. Training sessions have been organized to learn the driving conditions on the LT-UHV 4-STM, which will be the workhorse for the competition [5]. For the nano-race in spring 2017, nine teams over the world have expressed their interest to participate, one team gave up at the end of 2015 and six were finally selected by the organizers in May 2016.…”

Surface sensitivity of four-probe STM resistivity measurements of bulk ZnO correlated to XPS

“…[1][2][3] Since that era the technique has been commercialised and combined with numerous other in situ capabilities to achieve some incredible results on various surfaces and nanomaterials. Some notable results have refined our knowledge of defects in topological insulators using scanning tunnelling potentiometry, [4] contacting and manipulating single atoms at 4K, [5] tuning of atomic chains by chemisorption, [6] conductance measurements of self-assembled single layer molecules, [7] identification of metallic twin grain boundaries on monolayers, [8] charge transport in nanowires, [9][10][11][12][13] and using four-probe measurements to separate surface and atomic step conductivity from bulk conductivity. [14,15] In the area of sensors, where surface modification is typically used to induce a change in the electrical conductivity of a device, for example via adsorption, [16] covalent attachment or bio-functionalisation [17], understanding the details of surface modification and correlating these details with the changes in surface conductivity due to band bending and the influence of surface states is a crucial step in realising the potential of such devices.…”

Stabilization of Au Monatomic-High Islands on the (2×2)−Nad Reconstructed Surface of Wurtzite AlN(0001)

“…However, such single molecules have to be contacted to metallic nanoelectrodes, which should be two-dimensional (2D) islands with less than two monatomic layers in height to allow imaging the connected object with an atomic force microscope (AFM). These 2D islands are able to play the role of charge reservoirs or intermediate electrodes to be contacted by the tips of a multiprobe ultrahigh vacuum (UHV) instrument [15][16][17].…”