Time-resolved scanning tunnelling microscopy for molecular science

Sloan, Peter

doi:10.1088/0953-8984/22/26/264001

Cited by 20 publications

(18 citation statements)

References 113 publications

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“…To allow comparison with the new STS measurements, Figure presents a reanalysis, by way of a linear fit, of the voltage dependence of the desorption of chlorobenzene from Si(111)‐7×7 . These manipulation data were collected using the scanning method of manipulation, in which comparison of the number of adsorbates before and after the manipulation image yields the desorption probability. To determine the energy thresholds we now employ a linear fitting method and find three thresholds, at +2.1 ± 0.1 V, +2.7 ± 0.1 V and −1.3 ± 0.1 V, as shown in Figure .…”

Section: Stm and Sts Studies Of Chlorobenzene Desorption From Si(111)mentioning

confidence: 99%

Non‐Local Atomic Manipulation on Semiconductor Surfaces in the STM: The Case of Chlorobenzene on Si(111)‐7×7

Pan

Sloan

Palmer

2014

The Chemical Record

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Control over individual atoms with the scanning tunnelling microscope (STM) holds the tantalising prospect of atomic-scale construction, but is limited by its "one atom at a time" serial nature. "Remote control" through non-local STM manipulation-as we have demonstrated in the case of chlorobenzene on Si(111)-7×7-offers a new avenue for future "bottom-up" nanofabrication, since hundreds of chemical reactions may be carried out in parallel. Thus a good understanding of the non-local manipulation process, as provided by recent experiments, is important. Comparison of scanning tunnelling spectroscopy (STS) measurements of the bare Si(111)-7×7 surface and chemisorbed chlorobenzene molecules with the voltage dependence of the non-local STM-induced desorption of chlorobenzene proves particularly instructive. For example, the chlorobenzene LUMO appears at +0.9 V with respect to the Fermi level, whereas non-local manipulation thresholds are found at +2.1 V and +2.7 V. This difference supports a picture in which the voltage thresholds for non-local electron-induced desorption depend principally on the energies of the electronic states of the surface. Furthermore, the demonstration that the non-local process is largely insensitive to surface steps up to five layers in height suggests that either the electron transport in this process is subsurface in character or surface charge transport is responsible but is in some way unaffected by the steps.

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Section: Stm and Sts Studies Of Chlorobenzene Desorption From Si(111)mentioning

confidence: 99%

Non‐Local Atomic Manipulation on Semiconductor Surfaces in the STM: The Case of Chlorobenzene on Si(111)‐7×7

Pan

Sloan

Palmer

2014

The Chemical Record

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“…In order to test the timing performance of the gating setup, the injection pattern of BESSY II was imaged by shifting the gating window versus the storage ring's 1.25 MHz timing signal marking the single bunch. The ring was operated in the usual hybrid bunch mode, in which 3 4 of the orbit is filled by a multibunch pattern with 2 ns bunch separation. The remaining 1 4 of the orbit -corresponding to a time window of about 100 ns -is empty except for a single electron bunch placed in the middle of the empty (dark) zone.…”

Section: Resultsmentioning

confidence: 99%

“…In this course, several time-and laterally resolved experiments have been developed in recent years and have matured into well-established methods in various fields of research. [1][2][3][4][5][6] In general, one may distinguish between scanning and parallel imaging approaches, whereby the latter promise a much faster data acquisition.…”

Section: Introductionmentioning

confidence: 99%

Deflection gating for time-resolved x-ray magnetic circular dichroism–photoemission electron microscopy using synchrotron radiation

Wiemann

Kaiser

Cramm

et al. 2012

Review of Scientific Instruments

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In this paper, we present a newly developed gating technique for a time-resolving photoemission microscope. The technique makes use of an electrostatic deflector within the microscope's electron optical system for fast switching between two electron-optical paths, one of which is used for imaging, while the other is blocked by an aperture stop. The system can be operated with a switching time of 20 ns and shows superior dark current rejection. We report on the application of this new gating technique to exploit the time structure in the injection bunch pattern of the synchrotron radiation source BESSY II at Helmholtz-Zentrum Berlin for time-resolved measurements in the picosecond regime.

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“…One method, recently proposed by Yuan et al, Bandrauk's group [64], is utilizing the atto-second detection method of the coherent electronic dynamics in molecules with the temporal and spatial resolutions using the circularly polarized ultrashort UV pump and X-ray probe laser pulses. The other method is to utilize the time-resolved scanning microscopy (STM) and the magnetic force microscopy (MFM) to detect the ring current-induced magnetic fields during the ultrashort time [65][66][67].…”

Section: Application Of Current Localization Control To Anthracenementioning

confidence: 99%

Quantum Control of Coherent π-Electron Dynamics in Aromatic Ring Molecules

2021

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Herein we review a theoretical study of unidirectional π-electron rotation in aromatic ring molecules, which originates from two quasi-degenerate electronic excited states created coherently by a linearly polarized ultraviolet/visible laser with a properly designed photon polarization direction. Analytical expressions for coherent π-electron angular momentum, ring current and ring current-induced magnetic field are derived in the quantum chemical molecular orbital (MO) theory. The time evolution of the angular momentum and the ring current are expressed using the density matrix method under Markov approximation or by solving the time-dependent Schrödinger equation. In this review we present the results of the following quantum control scenarios after a fundamental theoretical description of coherent angular momentum, ring current and magnetic field: first, two-dimensional coherent π-electron dynamics in a non-planar (P)-2,2’-biphenol molecule; second, localization of the coherent π-electron ring current to a designated benzene ring in polycyclic aromatic hydrocarbons; third, unidirectional π-electron rotations in low-symmetry aromatic ring molecules based on the dynamic Stark shift of two relevant excited states that form a degenerate state using the non-resonant ultraviolet lasers. The magnetic fields induced by the coherent π-electron ring currents are also estimated, and the position dependence of the magnetic fluxes is demonstrated.

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Time-resolved scanning tunnelling microscopy for molecular science

Cited by 20 publications

References 113 publications

Non‐Local Atomic Manipulation on Semiconductor Surfaces in the STM: The Case of Chlorobenzene on Si(111)‐7×7

Non‐Local Atomic Manipulation on Semiconductor Surfaces in the STM: The Case of Chlorobenzene on Si(111)‐7×7

Deflection gating for time-resolved x-ray magnetic circular dichroism–photoemission electron microscopy using synchrotron radiation

Quantum Control of Coherent π-Electron Dynamics in Aromatic Ring Molecules

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