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Main Authors: Sivakumar, Nikhil S., Aretz, Joost, Scherb, Sebastian, Mavrič, Marion van Midden, Huijgen, Nora, Kamber, Umut, Wegner, Daniel, Khajetoorians, Alexander A., Rösner, Malte, Hauptmann, Nadine
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.17231
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author Sivakumar, Nikhil S.
Aretz, Joost
Scherb, Sebastian
Mavrič, Marion van Midden
Huijgen, Nora
Kamber, Umut
Wegner, Daniel
Khajetoorians, Alexander A.
Rösner, Malte
Hauptmann, Nadine
author_facet Sivakumar, Nikhil S.
Aretz, Joost
Scherb, Sebastian
Mavrič, Marion van Midden
Huijgen, Nora
Kamber, Umut
Wegner, Daniel
Khajetoorians, Alexander A.
Rösner, Malte
Hauptmann, Nadine
contents Scanning tunneling microscopy is the method of choice for characterizing charge density waves by imaging the variation in atomic-scale contrast of the surface. Due to the measurement principle of scanning tunneling microscopy, the electronic and lattice degrees of freedom are convoluted, making it difficult to disentangle a structural displacement from spatial variations in the electronic structure. In this work, we characterize the influence of the displacement of the surface-terminating Se atoms on the 3 x 3 charge density wave contrast in scanning probe microscopy images of 2H-NbSe$_2$. In scanning tunneling microscopy images, we observe the 3 x 3 charge density wave superstructure and atomic lattice at all probed tip-sample distances. In contrast, non-contact atomic force microscopy images show both periodicities only at small tip-sample distances while, unexpectedly, a 3 x 3 superstructure is present at larger tip-sample distances. Using density functional theory calculations, we qualitatively reproduce the experimental findings and indicate that the 3 x 3 superstructure at different tip-sample distances in non-contact atomic force microscopy images is a result from different underlying interactions. In addition, we show that the displacement of the surface-terminating Se atoms has a negligible influence to the contrast in scanning tunneling microscopy images. Our combined experimental and theoretic work presents a method on how to discriminate the influence of the surface corrugation from the variation of the charge density to the charge density wave contrast in scanning probe microscopy images, which can provide insights into the influence of structural disorder to a charge density wave ground state.
format Preprint
id arxiv_https___arxiv_org_abs_2407_17231
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Influence of surface relaxations on scanning probe microscopy images of the charge density wave material 2H-NbSe$_2$
Sivakumar, Nikhil S.
Aretz, Joost
Scherb, Sebastian
Mavrič, Marion van Midden
Huijgen, Nora
Kamber, Umut
Wegner, Daniel
Khajetoorians, Alexander A.
Rösner, Malte
Hauptmann, Nadine
Mesoscale and Nanoscale Physics
Scanning tunneling microscopy is the method of choice for characterizing charge density waves by imaging the variation in atomic-scale contrast of the surface. Due to the measurement principle of scanning tunneling microscopy, the electronic and lattice degrees of freedom are convoluted, making it difficult to disentangle a structural displacement from spatial variations in the electronic structure. In this work, we characterize the influence of the displacement of the surface-terminating Se atoms on the 3 x 3 charge density wave contrast in scanning probe microscopy images of 2H-NbSe$_2$. In scanning tunneling microscopy images, we observe the 3 x 3 charge density wave superstructure and atomic lattice at all probed tip-sample distances. In contrast, non-contact atomic force microscopy images show both periodicities only at small tip-sample distances while, unexpectedly, a 3 x 3 superstructure is present at larger tip-sample distances. Using density functional theory calculations, we qualitatively reproduce the experimental findings and indicate that the 3 x 3 superstructure at different tip-sample distances in non-contact atomic force microscopy images is a result from different underlying interactions. In addition, we show that the displacement of the surface-terminating Se atoms has a negligible influence to the contrast in scanning tunneling microscopy images. Our combined experimental and theoretic work presents a method on how to discriminate the influence of the surface corrugation from the variation of the charge density to the charge density wave contrast in scanning probe microscopy images, which can provide insights into the influence of structural disorder to a charge density wave ground state.
title Influence of surface relaxations on scanning probe microscopy images of the charge density wave material 2H-NbSe$_2$
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2407.17231