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Createc is your innovative partner in Molecular Beam Epitaxy MBE and LT-STM-AFM.
Molecular Beam Epitaxy (MBE) | Low Temperature Scanning Tunneling Microscopy (LT-STM) | Atomic Force Microscopy (AFM) | Ultra-high Vacuum (UHV) | Effusion Cells

Createc is your innovative partner in Molecular Beam Epitaxy MBE and LT-STM-AFM.

Spectroscopy of quantum wires


Topography (left) and quantum states (right) of a chain of Cu atoms on Cu(111).

Starting with a single Cu adatom on Cu(111), monatomic Cu chains can be successively assembled by means of lateral manipulation (left panel). Spectroscopy measurements reveal that these Cu chains represent 1D quantum wells as evident from a series of chain-localized bound states (center panel). The square of the wavefunction of the respective eigenstates (cf. for example dI/dV maps of a Cu7 chain, right panel) reveal clear quantum wire behavior.

LT-STM by CreaTec.

S. F?lsch, P. Hyldgaard, R. Koch, K. H. Ploog, Quantum Confinement in Monatomic Cu Chains on Cu(111), Phys. Rev. Lett. 92 (2004), 056803.


Charging single atoms


The STM image shows a charged and an uncharged Au-atom on a NaCl-covered Cu(111) surface.

Individual gold atoms on an ultrathin insulating sodium chloride film supported by a copper surface exhibit two different charge states, which are stabilized by the large ionic polarizability of the film. The charge state and associated physical and chemical properties such as diffusion and electron scattering can be controlled by adding or removing a single electron to or from the adatom with a scanning tunneling microscope tip.

The simple physical mechanism behind the charge bistability in this case suggests that this is a common phenomenon for adsorbates on polar insulating films.

LT-STM by CreaTec.

J. Repp, G. Meyer, F. E. Olsson, M. Persson, Controlling the charge state of individual gold adatoms, Science 305 (2004) 493.


Diffusion of adatoms


This movie shows the warming and the subsequent decay of an STM assembled nanostructure. It demonstrates the temperature variability as well a the superb stability of the CreaTec LT-STM. Cu/Cu(111).

2004-01-10


Surface state localization by adatoms


Calculated resonant wave function associated with the SSL state (left) and STS spectra for different lateral distances, R, revealing the adatom-localized resonance below the surface state band (right); The STM image (center) indicates the positions where spectra were taken.

A new type of electronic states at metal surfaces has been identified based on theoretical simulations and scanning tunneling spectroscopy (STS) of single Cu adatoms on the Cu(111) surface. The states, which we call surface state localization (SSL) states, are localized around the adatom, but do not derive from any atomic states of free Cu. Instead, the existence of such states can be understood from the adatom interacting with two-dimensional electronic states (Shockley surface states) that exist on many metal surfaces, such as Cu(111). First predicted by theory, the existence of these states has now been proven by STS measurements.

LT-STM by CreaTec.

F.E. Olsson, M. Persson, A.G. Borisov, J.-P. Gauyacq, J. Lagoute und S. F?lsch, Localization of the Cu(111) surface state by single Cu adatoms, Phys. Rev. Lett. 93 (2004) 206803.


Molecular Beam Epitaxy (MBE) | Low Temperature Scanning Tunneling Microscopy (LT-STM) | Atomic Force Microscopy (AFM) | Ultra-high Vacuum (UHV) | Effusion Cells