10 research outputs found
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Chemical Identification of Single Atoms in Heterogeneous III–IV Chains on Si(100) Surface by Means of nc-AFM and DFT Calculations
Chemical identification of individual atoms in mixed In–Sn chains grown on a Si(100)-(2 × 1) surface was investigated by means of room temperature dynamic noncontact AFM measurements and DFT calculations. We demonstrate that the chemical nature of each atom in the chain can be identified by means of measurements of the short-range forces acting between an AFM tip and the atom. On the basis of this method, we revealed incorporation of silicon atoms from the substrate into the metal chains. Analysis of the measured and calculated short-range forces indicates that even different chemical states of a single atom can be distinguished
Characteristic Contrast in Δ<i>f</i><sub>min</sub> Maps of Organic Molecules Using Atomic Force Microscopy
Scanning
tunneling microscopy and atomic force microscopy can provide detailed
information about the geometric and electronic structure of molecules
with submolecular spatial resolution. However, an essential capability
to realize the full potential of these techniques for chemical applications
is missing from the scanning probe toolbox: chemical recognition of
organic molecules. Here, we show that maps of the minima of frequency
shift–distance curves extracted from 3D data cubes contain
characteristic contrast. A detailed theoretical analysis based on
density functional theory and molecular mechanics shows that these
features are characteristic for the investigated species. Structurally
similar but chemically distinct molecules yield significantly different
features. We find that the van der Waals and Pauli interaction, together
with the specific adsorption geometry of a given molecule on the surface,
accounts for the observed contrast
Role of the Magnetic Anisotropy in Atomic-Spin Sensing of 1D Molecular Chains
One-dimensional
metal–organic chains often possess a complex
magnetic structure susceptible to modification by alteration of their
chemical composition. The possibility to tune their magnetic properties
provides an interesting playground to explore quasi-particle interactions
in low-dimensional systems. Despite the great effort invested so far,
a detailed understanding of the interactions governing the electronic
and magnetic properties of the low-dimensional systems is still incomplete.
One of the reasons is the limited ability to characterize their magnetic
properties at the atomic scale. Here, we provide a comprehensive study
of the magnetic properties of metal–organic one-dimensional
(1D) coordination polymers consisting of 2,5-diamino-1,4-benzoquinonediimine
ligands coordinated with Co or Cr atoms synthesized under ultrahigh-vacuum
conditions on a Au(111) surface. A combination of integral X-ray spectroscopy
with local-probe inelastic electron tunneling spectroscopy corroborated
by multiplet analysis, density functional theory, and inelastic electron
tunneling simulations enables us to obtain essential information about
their magnetic structures, including the spin magnitude and orientation
at the magnetic atoms, as well as the magnetic anisotropy
Large Converse Piezoelectric Effect Measured on a Single Molecule on a Metallic Surface
The converse piezoelectric effect
is a phenomenon in which mechanical
strain is generated in a material due to an applied electrical field.
In this work, we demonstrate the converse piezoelectric effect in
single heptahelicene-derived molecules on the Ag(111) surface using
atomic force microscopy (AFM) and total energy density functional
theory (DFT) calculations. The force–distance spectroscopy
acquired over a wide range of bias voltages reveals a linear shift
of the tip–sample distance at which the contact between the
molecule and tip apex is established. We demonstrate that this effect
is caused by the bias-induced deformation of the spring-like scaffold
of the helical polyaromatic molecules. We attribute this effect to
coupling of a soft vibrational mode of the molecular helix with a
vertical electric dipole induced by molecule–substrate charge
transfer. In addition, we also performed the same spectroscopic measurements
on a more rigid <i>o</i>-carborane dithiol molecule on the
Ag(111) surface. In this case, we identify a weaker linear electromechanical
response, which underpins the importance of the helical scaffold on
the observed piezoelectric response
Large Converse Piezoelectric Effect Measured on a Single Molecule on a Metallic Surface
The converse piezoelectric effect
is a phenomenon in which mechanical
strain is generated in a material due to an applied electrical field.
In this work, we demonstrate the converse piezoelectric effect in
single heptahelicene-derived molecules on the Ag(111) surface using
atomic force microscopy (AFM) and total energy density functional
theory (DFT) calculations. The force–distance spectroscopy
acquired over a wide range of bias voltages reveals a linear shift
of the tip–sample distance at which the contact between the
molecule and tip apex is established. We demonstrate that this effect
is caused by the bias-induced deformation of the spring-like scaffold
of the helical polyaromatic molecules. We attribute this effect to
coupling of a soft vibrational mode of the molecular helix with a
vertical electric dipole induced by molecule–substrate charge
transfer. In addition, we also performed the same spectroscopic measurements
on a more rigid <i>o</i>-carborane dithiol molecule on the
Ag(111) surface. In this case, we identify a weaker linear electromechanical
response, which underpins the importance of the helical scaffold on
the observed piezoelectric response