A cantilever-based, ultrahigh-vacuum, low-temperature scanning probe instrument for multidimensional scanning force microscopy

• Hao Liu,
• Zuned Ahmed,
• Sasa Vranjkovic,
• Manfred Parschau,
• Andrada-Oana Mandru and
• Hans J. Hug

Beilstein J. Nanotechnol. 2022, 13, 1120–1140, doi:10.3762/bjnano.13.95

• scanning tunneling microscope (STM) can be transformed into a tuning fork-based AFM simply by replacing the rigid STM tip by a tuning fork with an attached tip and by adding an extra pre-amplifier and a PLL to drive the tuning fork oscillation and measure shifts in its resonance frequency arising from the

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• beam current was measured by using a Faraday cup. The SAMs were irradiated with beam currents ranging from 200–600 pA. Prior to electron irradiation, the STM tip was retracted and moved away from the surface location of interest, such that the electrons could pass the tip and reach the surface location

• . The irradiated area was typically around 30 × 40 µm2. The time per cycle was 2.5 s. Imaging of SAMs by STM The STM experiments were performed on a commercial Omicron Multiscan system combining both a temperature-variable STM (Multiscan STM VT) and an SEM. The STM tip is aligned at ≈45° with respect to

• the surface normal, thus enabling to control the position of the STM tip by SEM. All STM data was acquired at room temperature under UHV conditions (chamber pressure <10−10 mbar). The STM was operated in constant-current mode with tunneling currents of 10–100 pA and sample biases between −1.2 to −0.4

Thermal oxidation process on Si(113)-(3 × 2) investigated using high-temperature scanning tunneling microscopy

• Hiroya Tanaka,
• Shinya Ohno,
• Kazushi Miki and
• Masatoshi Tanaka

Beilstein J. Nanotechnol. 2022, 13, 172–181, doi:10.3762/bjnano.13.12

• chamber with an STM apparatus (JEOL, JSTM-4500XT). The base pressure of the chamber equipped with the STM unit was kept at 5.0 × 10−9 Pa. For the high-temperature measurements, in order to make the temperature of the tip close to that of the sample, the STM tip was moved close (100 μm) to the sample and

Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

• Carl Drechsel,
• Philipp D’Astolfo,
• Jung-Ching Liu,
• Thilo Glatzel,
• Rémy Pawlak and
• Ernst Meyer

Beilstein J. Nanotechnol. 2022, 13, 1–9, doi:10.3762/bjnano.13.1

• by one with an STM tip in an one-dimensional fashion on an s-wave superconductor [10], this strategy has been primarily postponed in favor of self-assembly processes on Pb(110) surfaces [13][14][15][36]. Only recently, the successful manipulation of tens of Fe atoms has been reported on

• tip [66][67] to intentionally form dimers and trimers and measure their apparent STM heights. To do so, the STM tip was positioned above a single Fe atom. The resistance of the STM junction was then decreased from about 50 GΩ (imaging) to 3 GΩ (manipulation) in order to trap the Fe atom in the STM

• manipulations with the STM tip. In panel (f), the STM image shows the formation of a Fe trimer Fe3 by successive tip manipulations (imaging conditions, Vt = −30 mV, It = 60 pA). (g–i) Apparent STM heights extracted from panels (d–f) enabling one to distinguish from their topographic signatures Fe1, Fe2 and Fe3

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• nanoislands. Our STM data indicate that FePc molecules stay intact upon adsorption. While single molecules are trapped at surface defects and could be manipulated with the STM tip away from the defects onto the perfectly hydrogenated Ge(001):H surface, the major fraction of the molecules could be found within

• surrounding the island shows no signs of any discontinuity of the STM appearance. This makes the modification of the STM tip apex unlikely and points to the fact that the observed shift may originate from a real shift of the island on the Ge(001):H surface. This observation indicates a weak interaction

• -point spectrum recorded on the FePc island. For clarity, the inset indicates the lateral position of the STM tip during measurements. Within the data we can clearly notice the presence of narrow resonances centered at approximately −1.34 V and +1.36 V, which are separated by a flat part of the spectrum

TiO_x/Pt₃Ti(111) surface-directed formation of electronically responsive supramolecular assemblies of tungsten oxide clusters

• Marco Moors,
• Yun An,
• Agnieszka Kuc and
• Kirill Yu. Monakhov

Beilstein J. Nanotechnol. 2021, 12, 203–212, doi:10.3762/bjnano.12.16

• , theory-supported STM measurements at liquid nitrogen temperatures have been selected as an ideal characterization technique. This is due to the fact that it not only allows high-resolution imaging on the nanoscale, but the STM tip may also act as a charge-injecting or depleting electrode for the

• . Hereby, the clusters appear in the typical triangular form with a side length of 13.0 ± 0.5 Å and a maximum height of 2.0 ± 0.2 Å. An STM tip-induced manipulation of single clusters was not possible within practically manageable voltage and current limits. The rather high stability may be due to a strong

• interaction with the substrate. The exclusive positioning of the W3O9 clusters on the point defects inside the trenches leads us to the conclusion that the preferred interaction with the metallic substrate below the oxide film compensates any charge injection or removal induced by the STM tip. For that

PTCDA adsorption on CaF₂ thin films

• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1615–1622, doi:10.3762/bjnano.11.144

• in (c). The topography image in (d) presenting PTCDA on a mixed CaF2 and CaF1/Si(111) surface is used for the statistical analysis in (b). STM data acquired on a CaF1/Si(111) surface area (e) before and (f) after accidental removal of single PTCDA molecules by the STM tip. Stationary molecules are

Adsorption and self-assembly of porphyrins on ultrathin CoO films on Ir(100)

• Feifei Xiang,
• Tobias Schmitt,
• Marco Raschmann and
• M. Alexander Schneider

Beilstein J. Nanotechnol. 2020, 11, 1516–1524, doi:10.3762/bjnano.11.134

• imaged as a protrusion on CoO for tunneling bias voltages of ±2.0 V around the Fermi energy. In Figure 5 we analyze the behavior of 1 on the 2BL CoO film. Imaging of 1 proved difficult at liquid-nitrogen temperatures since the molecules are easily pulled by the STM tip even at junction resistances of RT

• = 10 GΩ. When molecules remain in place, they are imaged as round doughnut-like objects with four positions along the ring, which are imaged brighter (Figure 5a). By manipulating the molecules with the STM tip, we almost never detected a defect in the oxide layer at which the molecules might have been

Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

• Robby Reynaerts,
• Kunal S. Mali and
• Steven De Feyter

Beilstein J. Nanotechnol. 2020, 11, 1291–1302, doi:10.3762/bjnano.11.113

• layer. We discovered that the self-assembly on top of the buffer layer allows better control over the nanoscale manipulation of the self-assembled networks. Using the influence of the STM tip, we could initiate the nucleation of small isolated domains of the benzoic acid on-command in a reproducible

• significant reorganization of domains upon repeated scanning with the STM tip (Figure S3 in Supporting Information File 1). Figure 3a,b shows a typical high-resolution STM image of the n-C50 buffer layer together with the proposed molecular model for the assembly. n-C50 monolayers consist of a lamellar

• possible for monolayers adsorbed directly on the graphite surface. In the following section we describe our attempts to observe such dynamic phenomena and to induce nucleation of BA-OC14 domains using the STM tip. STM tip-induced nucleation on-command atop n-C50 buffer layer During the course of this

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• liquid-cell in a custom-built liquid-STM setup [7]. The STM-tip (mechanically cut) was immersed in a typical volume of 350 µL of the solution. The used concentrations of porphyrin varied between 1 × 10−4 and 1 × 10−3 M and are mentioned at the relevant experiments in the main text. The STM measurements

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• . However, it is also possible to induce irreversible switching of the molecular geometry by application of a voltage pulse applied from the STM tip. Figure 4 presents the area before (Figure 4a) and after (Figure 4b) application of a bias voltage pulse above the center of a Sn-up Pc molecule, pointed out

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• regimes, the shape of the Kondo resonance is influenced by the Fano resonance. However, the tunneling between the STM tip and graphene does not obviously affect the shape of the Kondo resonance in the vicinity of zero bias. Yanagisawa investigated the Kondo effect induced by the s–d interaction with Dirac

Nanosecond resistive switching in Ag/AgI/PtIr nanojunctions

• Botond Sánta,
• Dániel Molnár,
• Patrick Haiber,
• Agnes Gubicza,
• Edit Szilágyi,
• Zsolt Zolnai,
• András Halbritter and
• Miklós Csontos

Beilstein J. Nanotechnol. 2020, 11, 92–100, doi:10.3762/bjnano.11.9

• formed in a vacuum chamber that can be evacuated down to 10−7 mbar. The thin film sample and the STM tip are mechanically attached directly to the hot lines of two impedance-matched co-planar waveguide printed circuit boards (PCBs). Their common ground is provided by a spring-loaded contact, which

• ensures stable connection also during the mechanical adjustments of the STM junction. The PCBs hosting the STM tip and the thin film sample are mounted on a linear stage and on an XZ piezo actuator, respectively. The former is responsible for the coarse approach of the tip whereas the latter is used for

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• conductivity in the OSC SAMs, brought about by transfer of charge from the molecule contacted by the STM tip to neighboring molecules. The presence of islands with different apparent height in OSC-based SAMs could be confirmed later for the case of hexabenzocoronene (HBC)-thiolates by Käfer et al. [28]. They

Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower

• Rouzhaji Tuerhong,
• Mauro Boero and
• Jean-Pierre Bucher

Beilstein J. Nanotechnol. 2019, 10, 1243–1250, doi:10.3762/bjnano.10.124

• level [21]. By approaching the STM tip towards a molecule on the Au(111) surface, it is possible to transfer a single MnPc molecule from the surface to the tip apex of the STM. Then the presence of a molecule on the tip can be directly confirmed by the reverse transfer process, i.e., by applying a

• voltage pulse on the tip or by scanning a clean surface area with this molecule-terminated tip until the molecule drops back from the STM tip to the surface. Since the voltage pulse applied to a phthalocyanine molecule may induce a chemical modification of the molecule through dehydrogenation [13][15

• dropping the molecule at an elbow site of the Au(111) reconstruction, indicated by the arrow in Figure 1b, the STM image improves significantly and the surface reconstruction of Au(111) becomes clearly visible. It should be emphasized that only one molecule is deposited from the STM tip on the surface as

Capillary force-induced superlattice variation atop a nanometer-wide graphene flake and its moiré origin studied by STM

• Loji K. Thomas and
• Michael Reichling

Beilstein J. Nanotechnol. 2019, 10, 804–810, doi:10.3762/bjnano.10.80

• -sized graphene flake wherein we have induced a further rotation of the flake utilizing the capillary forces at play at a solid–liquid interface using STM tip motion. We propose a more “realistic” tip–surface meniscus relevant to STM at solid–liquid interfaces and show that the capillary force is

• [50] or about problems in capillary mechanics, we point out a major difference in the meniscus formation at an STM tip–surface interface. Here, the distance s, between the surface and the STM tip is not decided by the requirement for meniscus formation, rather it is defined by the STM operating

• parameter namely the set point current (in constant-current mode), which fixes the tip–surface separation stip–surf. The STM tip is usually immersed in the liquid and therefore the distance s is always greater than or equal to stip–surf. Further, the meniscus is not static but in motion due to the raster

Intuitive human interface to a scanning tunnelling microscope: observation of parity oscillations for a single atomic chain

• Sumit Tewari,
• Jacob Bakermans,
• Christian Wagner,
• Federica Galli and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2019, 10, 337–348, doi:10.3762/bjnano.10.33

• refer to as point contact pushing (PCP) technique. Keywords: adatom imaging; mechanical annealing; scanning tunnelling microscopy (STM); STM tip; tip apex; Introduction It is of fundamental interest both for chemists and physicists to study the electronic transport through single atoms and molecules

• image the structural changes that happen at the junction using the STM, because the very STM tip used for imaging is also used for manipulation. It is known that the electronic transport of these nanoscale devices depends strongly on their structural conformations and coupling to the leads [3][4

• LabVIEW is used to control the STM tip in all three dimensions during manipulation. Figure 1 shows the schematic diagram of the complete setup with 3D motion controller and the MD real-time simulator. The 3D motion control system is an LED tracker made with two cameras tracking the x–y-motion and y–z

Directional light beams by design from electrically driven elliptical slit antennas

• Shuiyan Cao,
• Eric Le Moal,
• Quanbo Jiang,
• Aurélien Drezet,
• Serge Huant,
• Jean-Paul Hugonin,
• Gérald Dujardin and
• Elizabeth Boer-Duchemin

Beilstein J. Nanotechnol. 2018, 9, 2361–2371, doi:10.3762/bjnano.9.221

• top of an inverted optical microscope. The setup is described in detail in the Experimental section. Circular or elliptical slits are etched in an optically thick (200 nm) gold film deposited on a glass coverslip. The inelastic effects of the tunnel current between the STM tip and the surface of the

• numerical aperture (NA) microscope objective. The angular distribution of the emitted light is acquired from Fourier-space images [24][25]. The angular emission pattern results from the far-field interference of the light scattered from all along the slit. When the STM tip is positioned in the center of the

• -space images recorded upon excitation with the tunnel electrons from the STM tip at one of the focii are shown in Figure 4d–f. Good agreement is found between the experimental data and the simulated images shown in Figure 4g–i. These simulated images are obtained using a model based on an ensemble of in

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• the Kondo and the leaking Majorana quasiparticle can be confronted with each other. These magnetically polarized YSR and Majorana quasiparticles as well as the subgap Kondo effect can be experimentally verified using tunneling heterostructures with ferromagnetic lead (STM tip). Results and Discussion

• geometry relevant to the recent experimental situation addressed by A. Yazdani and co-workers [42], which can be described by the following Hamiltonian We assume here that the STM tip describes a polarized fermion gas where the energy can be controlled by some finite detuning of the chemical potentials

• μN↑ − μN↓. Individual atoms of the nanochain are coupled with such STM tip through For simplicity, we assume constant couplings The low-energy physics of such proximitized Rashba nanowire can be described by [44] where annihilates (creates) an electron of spin σ at site i with energy εi, and tij

Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study

• Hao Tang,
• Nathalie Tarrat,
• Véronique Langlais and
• Yongfeng Wang

Beilstein J. Nanotechnol. 2017, 8, 2484–2491, doi:10.3762/bjnano.8.248

• vacuum disappears upon adsorption on the metal surfaces. The high-spin state of physisorbed FeTPP is stable on all adsorption sites. This result reveals that an external permanent element such as a STM tip or an additional molecule is needed to use FeTPP or similar molecules as model system for molecular

• S = 1 associated with a conformational change by passing from a saddle shape to a planar shape in the presence of the STM tip. To the best of our knowledge, the stability as well as the activation barrier between HS and IS FeTPP have not yet been investigated. In this paper, a brief analysis of the

• strong enough to modify the ligand-field environment of Fe. This result reveals that an external permanent element such as a STM tip or an additional molecule is needed to use FeTPP or similar molecules as model system for molecular spin switches. Method and Computational Details Spin-polarized DFT

Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

• Sumit Tewari,
• Koen M. Bastiaans,
• Milan P. Allan and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2017, 8, 2389–2395, doi:10.3762/bjnano.8.238

• the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up

• to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes. Keywords: adatom imaging; mechanical annealing; scanning tunneling microscopy (STM); STM tip; tip apex; Introduction After the advent of the scanning tunneling microscope (STM) in 1981

• shape [15]. Controlled manipulation by STM of adatoms and molecules on metal surfaces depends also on the precise knowledge and reproducibility of the atomic tip structure. In the field of molecular electronics, where researchers are now trying to connect single molecules between an STM tip and a flat

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• itself to approximate expansions in the tunneling between the molecule and the leads. The method is thus powerful for strong interactions but weak hybridization between the molecules and the electrodes (STM tip and substrate). The ME approach requires the formal separation of the system into the molecule

• function of the bias voltage is obtained from the spin-polarized current within the DFT-NEGF method. Absolute value squared of the tunneling amplitude a) between the STM tip and a CoPc HOMO on a graphene substrate and b) between the tip and a representative low-energy Bloch-type substrate state, as

Coexistence of strongly buckled germanene phases on Al(111)

• Weimin Wang and
• Roger I. G. Uhrberg

Beilstein J. Nanotechnol. 2017, 8, 1946–1951, doi:10.3762/bjnano.8.195

• might be displaced by the interaction with the STM tip (external electric field applied during scanning). In this paper, we present new data on the Ge/Al(111) system which significantly broadens the view on germanene formation. We show that it is possible to grow well-ordered monolayer Ge at

Structural model of silicene-like nanoribbons on a Pb-reconstructed Si(111) surface

• Agnieszka Stępniak-Dybala and
• Mariusz Krawiec

Beilstein J. Nanotechnol. 2017, 8, 1836–1843, doi:10.3762/bjnano.8.185

• additional argument for the Si nature of nanoribbons can be provided by measurements of the local work function (Φ). In a first approximation Φ is proportional to the derivative of the tunneling current (I) with respect to the STM tip–sample distance (z) [55]. Thus, changes of Φ should be reflected in