Scanning Tunneling Microscopy Study of Epitaxial Fe3GeTe2 Monolayers on Bi2Te3

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Hauptverfasser: Goff, Brad M., Bishop, Alexander J., Zhou, Wenyi, Bailey-Crandell, Ryan, Robinson, Katherine, Kawakami, Roland K., Gupta, Jay A.
Format: Preprint
Veröffentlicht: 2023
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author Goff, Brad M.
Bishop, Alexander J.
Zhou, Wenyi
Bailey-Crandell, Ryan
Robinson, Katherine
Kawakami, Roland K.
Gupta, Jay A.
author_facet Goff, Brad M.
Bishop, Alexander J.
Zhou, Wenyi
Bailey-Crandell, Ryan
Robinson, Katherine
Kawakami, Roland K.
Gupta, Jay A.
contents Introducing magnetism to the surface state of topological insulators, such as Bi2Te3, can lead to a variety of interesting phenomena. We use scanning tunneling microscopy (STM) to study a single quintuple layer (QL) of the van der Waals magnet Fe3GeTe2 (FGT) that is grown on Bi2Te3 via molecular beam epitaxy. STM topographic images show that the FGT grows as free-standing islands on Bi2Te3 and outwards from Bi2Te3 steps. Atomic resolution imaging shows atomic lattices of 390 +- 10 pm for FGT and 430 +- 10 pm for Bi2Te3, consistent with the respective bulk crystals. A moiré pattern is observed on FGT regions with a periodicity of 4.3 +- 0.4 nm that can be attributed solely to this lattice mismatch and thus indicates zero rotational misalignments. While most of the surface is covered by a single QL of the FGT, there are small double QL regions, as well as regions with distinct chemical terminations due to an incomplete QL. The most common partial QL surface termination is the FeGe layer, in which the top two atomic layers are missing. This termination has a distinctive electronic structure and a (sqrt3 x sqrt3)R30 reconstruction overlaid on the moiré pattern in STM images. Magnetic circular dichroism (MCD) measurements confirm these thin FGT films are ferromagnetic with TC ~190 K.
format Preprint
id arxiv_https___arxiv_org_abs_2303_10113
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Scanning Tunneling Microscopy Study of Epitaxial Fe3GeTe2 Monolayers on Bi2Te3
Goff, Brad M.
Bishop, Alexander J.
Zhou, Wenyi
Bailey-Crandell, Ryan
Robinson, Katherine
Kawakami, Roland K.
Gupta, Jay A.
Materials Science
Introducing magnetism to the surface state of topological insulators, such as Bi2Te3, can lead to a variety of interesting phenomena. We use scanning tunneling microscopy (STM) to study a single quintuple layer (QL) of the van der Waals magnet Fe3GeTe2 (FGT) that is grown on Bi2Te3 via molecular beam epitaxy. STM topographic images show that the FGT grows as free-standing islands on Bi2Te3 and outwards from Bi2Te3 steps. Atomic resolution imaging shows atomic lattices of 390 +- 10 pm for FGT and 430 +- 10 pm for Bi2Te3, consistent with the respective bulk crystals. A moiré pattern is observed on FGT regions with a periodicity of 4.3 +- 0.4 nm that can be attributed solely to this lattice mismatch and thus indicates zero rotational misalignments. While most of the surface is covered by a single QL of the FGT, there are small double QL regions, as well as regions with distinct chemical terminations due to an incomplete QL. The most common partial QL surface termination is the FeGe layer, in which the top two atomic layers are missing. This termination has a distinctive electronic structure and a (sqrt3 x sqrt3)R30 reconstruction overlaid on the moiré pattern in STM images. Magnetic circular dichroism (MCD) measurements confirm these thin FGT films are ferromagnetic with TC ~190 K.
title Scanning Tunneling Microscopy Study of Epitaxial Fe3GeTe2 Monolayers on Bi2Te3
topic Materials Science
url https://arxiv.org/abs/2303.10113