Contrast stability and 'stripe' formation in scanning tunnelling microscopy imaging of highly oriented pyrolytic graphite: The role of STM-tip orientations

Gábor Mándi, Gilberto Teobaldi, K. Palotás

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Highly oriented pyrolytic graphite (HOPG) is an important substrate in many technological applications and is routinely used as a standard in Scanning Tunnelling Microscopy (STM) calibration, which makes the accurate interpretation of the HOPG STM contrast of great fundamental and applicative importance. We demonstrate by STM simulations based on electronic structure obtained from first principles that the relative local orientation of the STM-tip apex with respect to the HOPG substrate has a considerable effect on the HOPG STM contrast. Importantly for experimental STM analysis of HOPG, the simulations indicate that local tip-rotations maintaining a major contribution of the d3z2-r2 tip-apex state to the STM current affect only the secondary features of the HOPG STM contrast resulting in 'stripe' formation and leaving the primary contrast unaltered. Conversely, tip-rotations leading to enhanced contributions from m ≠ 0 tip-apex electronic states can cause a triangular-hexagonal change in the primary contrast. We also report a comparison of two STM simulation models with experiments in terms of bias-voltage-dependent STM topography brightness correlations and discuss our findings for the HOPG(0 0 0 1) surface in combination with tungsten tip models of different sharpnesses and terminations.

Original languageEnglish
Article number485007
JournalJournal of Physics Condensed Matter
Volume26
Issue number48
DOIs
Publication statusPublished - Dec 3 2014

Fingerprint

Graphite
pyrolytic graphite
Scanning tunneling microscopy
scanning tunneling microscopy
Imaging techniques
apexes
Tungsten
simulation
Electronic states
Substrates
Bias voltage
Topography
Electronic structure
Luminance
topography
tungsten
brightness
Calibration
electronic structure

Keywords

  • HOPG
  • STM contrast
  • STM tip orientation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)

Cite this

@article{6591c2e07e714a8d85d8244cbeae1bcf,
title = "Contrast stability and 'stripe' formation in scanning tunnelling microscopy imaging of highly oriented pyrolytic graphite: The role of STM-tip orientations",
abstract = "Highly oriented pyrolytic graphite (HOPG) is an important substrate in many technological applications and is routinely used as a standard in Scanning Tunnelling Microscopy (STM) calibration, which makes the accurate interpretation of the HOPG STM contrast of great fundamental and applicative importance. We demonstrate by STM simulations based on electronic structure obtained from first principles that the relative local orientation of the STM-tip apex with respect to the HOPG substrate has a considerable effect on the HOPG STM contrast. Importantly for experimental STM analysis of HOPG, the simulations indicate that local tip-rotations maintaining a major contribution of the d3z2-r2 tip-apex state to the STM current affect only the secondary features of the HOPG STM contrast resulting in 'stripe' formation and leaving the primary contrast unaltered. Conversely, tip-rotations leading to enhanced contributions from m ≠ 0 tip-apex electronic states can cause a triangular-hexagonal change in the primary contrast. We also report a comparison of two STM simulation models with experiments in terms of bias-voltage-dependent STM topography brightness correlations and discuss our findings for the HOPG(0 0 0 1) surface in combination with tungsten tip models of different sharpnesses and terminations.",
keywords = "HOPG, STM contrast, STM tip orientation",
author = "G{\'a}bor M{\'a}ndi and Gilberto Teobaldi and K. Palot{\'a}s",
year = "2014",
month = "12",
day = "3",
doi = "10.1088/0953-8984/26/48/485007",
language = "English",
volume = "26",
journal = "Journal of Physics Condensed Matter",
issn = "0953-8984",
publisher = "IOP Publishing Ltd.",
number = "48",

}

TY - JOUR

T1 - Contrast stability and 'stripe' formation in scanning tunnelling microscopy imaging of highly oriented pyrolytic graphite

T2 - The role of STM-tip orientations

AU - Mándi, Gábor

AU - Teobaldi, Gilberto

AU - Palotás, K.

PY - 2014/12/3

Y1 - 2014/12/3

N2 - Highly oriented pyrolytic graphite (HOPG) is an important substrate in many technological applications and is routinely used as a standard in Scanning Tunnelling Microscopy (STM) calibration, which makes the accurate interpretation of the HOPG STM contrast of great fundamental and applicative importance. We demonstrate by STM simulations based on electronic structure obtained from first principles that the relative local orientation of the STM-tip apex with respect to the HOPG substrate has a considerable effect on the HOPG STM contrast. Importantly for experimental STM analysis of HOPG, the simulations indicate that local tip-rotations maintaining a major contribution of the d3z2-r2 tip-apex state to the STM current affect only the secondary features of the HOPG STM contrast resulting in 'stripe' formation and leaving the primary contrast unaltered. Conversely, tip-rotations leading to enhanced contributions from m ≠ 0 tip-apex electronic states can cause a triangular-hexagonal change in the primary contrast. We also report a comparison of two STM simulation models with experiments in terms of bias-voltage-dependent STM topography brightness correlations and discuss our findings for the HOPG(0 0 0 1) surface in combination with tungsten tip models of different sharpnesses and terminations.

AB - Highly oriented pyrolytic graphite (HOPG) is an important substrate in many technological applications and is routinely used as a standard in Scanning Tunnelling Microscopy (STM) calibration, which makes the accurate interpretation of the HOPG STM contrast of great fundamental and applicative importance. We demonstrate by STM simulations based on electronic structure obtained from first principles that the relative local orientation of the STM-tip apex with respect to the HOPG substrate has a considerable effect on the HOPG STM contrast. Importantly for experimental STM analysis of HOPG, the simulations indicate that local tip-rotations maintaining a major contribution of the d3z2-r2 tip-apex state to the STM current affect only the secondary features of the HOPG STM contrast resulting in 'stripe' formation and leaving the primary contrast unaltered. Conversely, tip-rotations leading to enhanced contributions from m ≠ 0 tip-apex electronic states can cause a triangular-hexagonal change in the primary contrast. We also report a comparison of two STM simulation models with experiments in terms of bias-voltage-dependent STM topography brightness correlations and discuss our findings for the HOPG(0 0 0 1) surface in combination with tungsten tip models of different sharpnesses and terminations.

KW - HOPG

KW - STM contrast

KW - STM tip orientation

UR - http://www.scopus.com/inward/record.url?scp=84910621054&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84910621054&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/26/48/485007

DO - 10.1088/0953-8984/26/48/485007

M3 - Article

AN - SCOPUS:84910621054

VL - 26

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 48

M1 - 485007

ER -