Influence of resonant tunneling on the imaging of atomic defects on InAs(110) surfaces by low-temperature scanning tunneling microscopy

We study the local density of states at and around a substituting impurity and use these results to compute current versus bias characteristic curves of Scanning Tunneling Microscopy (STM) experiments done on the surface of graphene. This allow us to detect the presence of substituting impurities on graphene. The case of vacancies is also analyzed. We find that the shape and magnitude of the STM characteristic curves depend on the position of the tip and on the nature of the ...

We report on a fully nonequilibrium theory of the scanning tunneling microscopy (STM) through resonances induced by impurity atoms adsorbed on metal surfaces. The theory takes into account the effect of the tunneling current and finite bias on the system and is valid for arbitrary intra-adsorbate electron correlation strength. It is thus applicable to the recent STM experiments on Kondo impurities.

We report the study of single dangling bonds (DB) on the hydrogen terminated silicon (100) surface using a low temperature scanning tunneling microscope (LT-STM). By investigating samples prepared with different annealing temperatures, we establish the critical role of subsurface arsenic dopants on the DB electronic properties. We show that when the near surface concentration of dopants is depleted as a result of $1250{\deg}C$ flash anneals, a single DB exhibits a sharp condu...

We have used scanning tunneling microscopy to identify individual phosphorus dopant atoms near the clean silicon (100)-(2x1) reconstructed surface. The charge-induced band bending signature associated with the dopants shows up as an enhancement in both filled and empty states and is consistent with the appearance of n-type dopants on compound semiconductor surfaces and passivated Si(100)-(2x1). We observe dopants at different depths and see a strong dependence of the signatur...

We present an atomically resolved study of metal-organic vapor epitaxy grown Mn doped InSb that is ferromagnetic at room-temperature. Both topographic and spectroscopic measurements have been performed by cross-sectional scanning tunneling microscopy. The measurements show a perfect crystal structure without any precipitates and reveal that Mn acts as a shallow acceptor. The Mn concentration obtained from the cross-sectional STM data compares well with the intended doping con...

Scanning Tunneling Microscopy (STM) is a powerful technique that utilizes quantum tunneling to visualize atomic surfaces with high precision. This study presents detailed topographic maps and evaluates the local density of states (LDOS) for three distinct materials: Highly Oriented Pyrolytic Graphite (HOPG), gold, and silicon. By meticulously measuring the tunneling current from a finely pointed tip positioned nanometers above the sample, we successfully image the surface top...

Cross-sectional scanning tunneling microscopy (X-STM) was employed to characterize the InAs submonolayer quantum dots (SMLQDs) grown on top of a Si-doped GaAs(001) substrate in the presence of (2X4) and c(4X4) surface reconstructions. Multiple layers were grown under different conditions to study their effects on the formation, morphology and local composition of the SMLQDs. The morphological and compositional variations in SMLQDs were observed by both filled and emptystate i...

We study the light emission from a Ag(111) surface when the bias voltage on a scanning tunneling microscope (STM) junction is ramped into the field emission regime. Above the vacuum level, scanning tunneling spectroscopy (STS) shows a series of well defined resonances associated with the image states of the surface, which are Stark shifted due to the electric field provided by the STM tip. We present photon--energy resolved measurements that unambiguously show that the mechan...

The reconstruction on Ge(001) surface is locally and reversibly changed between c(4x2) and p(2x2) by controlling the bias voltage of a scanning tunneling microscope (STM) at 80K. It is c(4x2) with the sample bias voltage V_b =< -0.7V. This structure can be kept with V_b =< 0.6V. When V_b is higher than 0.8V during the scanning, the structure changes to p(2x2). This structure is then maintained with V_b >= - 0.6V. The observed local change of the reconstruction with hysteresis...

Theoretical understanding of scanning tunnelling microscope (STM) measurements involve electronic structure details of the STM tip and the sample being measured. Conventionally, the focus has been on the accuracy of the electronic state simulations of the sample, whereas the STM tip electronic state is typically approximated as a simple spherically symmetric $ s $ orbital. This widely used $ s $ orbital approximation has failed in recent STM studies where the measured STM ima...