Local density of states from constant-current tunneling spectra

Ziegler, Martin; Néel, N.; Sperl, Alexander; Berndt, Richard

doi:10.1103/physrevb.80.125402

Cited by 76 publications

(69 citation statements)

References 41 publications

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“…A 9 × 9 matrix from the considered orbitals is obtained, where the orbitals are denoted by numbers 1 to 9 following the indices reported in Table 2. One finds that most contributions are due to the s (1), p z (3), d yz (6), d 3z 2 −r 2 (7), and d xz (8) orbitals and their combinations. The largest contribution to the current is given by the d 3z 2 −r 2 − d 3z 2 −r 2 (7-7) transition, 31 and 20 per cent above the top and hollow positions, respectively.…”

Section: Orbital Contributionsmentioning

confidence: 99%

“…One is inspired by the Tersoff-Hamann model, taking only surface properties into account, see Eq. (8). Note that this formula does not have an explicit bias dependence.…”

Section: Transmissionmentioning

confidence: 99%

“…Alternatively, a simpler model for κ(E) can be considered without Vdependence as in Eq. (8). In this case the background term of the differential conductance B(V ) in Eq.…”

Section: Di/dv Contributionsmentioning

confidence: 99%

“…The largest contribution to the current is given by the d 3z 2 −r 2 − d 3z 2 −r 2 (7-7) transition, 31 and 20 per cent above the top and hollow positions, respectively. Concomitantly, above the hollow position, the relative importance of both tip and sample d yz (6) and d xz (8) orbitals is increased as it is expected from the geometrical setup, i.e., the d yz − d yz , d yz − d 3z 2 −r 2 (6-7 and 7-6), d xz −d xz , and d xz −d 3z 2 −r 2 (7-8 and 8-7) contributions correspond to larger orientational overlap of the mentioned tip and sample orbitals if the tip is above the hollow position rather than above the top position as suggested by the geometry in Fig. 14 and Eq.…”

Section: Orbital Contributionsmentioning

confidence: 99%

“…One direction of recent theoretical research is focused on extracting surface local electronic properties from experimental STS data [5][6][7][8][9], which is the convolution of tip and sample electronic structures. Applying STS in the spin-polarized setup, this research line could be extended to the possible extraction of local spin polarization information of surfaces.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional Wentzel-Kramers-Brillouin approach for the simulation of scanning tunneling microscopy and spectroscopy

2013

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We review the recently developed three-dimensional (3D) atom-superposition approach for simulating scanning tunneling microscopy (STM) and spectroscopy (STS) based on ab initio electronic structure data. In the method, contributions from individual electron tunneling transitions between the tip apex atom and each of the sample surface atoms are summed up assuming the one-dimensional (1D) Wentzel-Kramers-Brillouin (WKB) approximation in all these transitions. This 3D WKB tunneling model is extremely suitable to simulate spin-polarized STM and STS on surfaces exhibiting a complex noncollinear magnetic structure, i.e., without a global spin quantization axis, at very low computational cost. The tip electronic structure from first principles can also be incorporated into the model, that is often assumed to be constant in energy in the vast majority of the related literature, which could lead to a misinterpretation of experimental findings. Using this approach, we highlight some of the electron tunneling features on a prototype frustrated hexagonal antiferromagnetic Cr monolayer on Ag(111) surface. We obtain useful theoretical insights into the simulated quantities that is expected to help the correct evaluation of experimental results. By extending the method to incorporate a simple orbital dependent electron tunneling transmission, we reinvestigate the bias voltage-and tip-dependent contrast inversion effect on the W(110) surface. STM images calculated using this orbital dependent model agree reasonably well with Tersoff-Hamann and Bardeen results. The computational efficiency of the model is remarkable as the k-point samplings of the surface and tip Brillouin zones do not affect the computational time, in contrast to the Bardeen method. In a certain case we obtain a relative computational time gain of 8500 compared to the Bardeen calculation, without the loss of quality. We discuss the advantages and limitations of the 3D WKB method, and show further ways to improve and extend it.

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Section: Orbital Contributionsmentioning

confidence: 99%

“…One is inspired by the Tersoff-Hamann model, taking only surface properties into account, see Eq. (8). Note that this formula does not have an explicit bias dependence.…”

Section: Transmissionmentioning

confidence: 99%

“…Alternatively, a simpler model for κ(E) can be considered without Vdependence as in Eq. (8). In this case the background term of the differential conductance B(V ) in Eq.…”

Section: Di/dv Contributionsmentioning

confidence: 99%

Section: Orbital Contributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Three-dimensional Wentzel-Kramers-Brillouin approach for the simulation of scanning tunneling microscopy and spectroscopy

2013

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Scanning Probe Microscopy – From Surfaces to Single Atoms

Néel

2020

Digital Encyclopedia of Applied Physics

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This article highlights the important role of scanning tunneling and atomic force microscopy in modern surface science experiments. Imaging with atomic resolution, manipulation of matter atom by atom, spectroscopy of confined electrons, molecular vibrational quanta, surface phonons, single‐atom spin flips, and single‐molecule fluorescence photons are some of the diverse applications of the microscopes. The impact of the actual atomic or molecular termination of the tip is emphasized. A variety of examples presents the state of the art in quantum physics of surfaces and interfaces and demonstrates that scanning probe techniques significantly contribute to the understanding of matter at the atomic scale.

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