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Scanning tunneling microscopy of molecules at metal interfaces


Liu, Danyang. Scanning tunneling microscopy of molecules at metal interfaces. 2023, University of Zurich, Faculty of Science.

Abstract

Table of contents
1 Introduction 1
2 Scanning tunneling microscopy 3
2.1 Basics of scanning tunneling microscopy (STM)........................................... 3
2.2 Basics of scanning tunneling spectroscopy (STS)........................................ 4
2.2.1 Tersoff-Hamann Approximation........................................................ 4
2.2.2 Lock-in technique for di/dNmeasurement...................................... 5
2.2.3 Energy resolution in STS.................................................................... 6
3 Molecule growth on metallic surfaces 7
3.1 PTCDA mediated Ag(l 11) step edge faceting as a precursor of pinwheel phase 7
3.1.1 Pinwheel phase growth....................................................................... 7
3.1.2 Pinwheel structure analysis................................................................. 9
3.1.3 Electronic properties of the pinwheel phase..................................... 13
3.1.4 PTCDA decorated Ag( 111) step edge............................................... 14
3.1.5 Surface reconstruction as a template for quantum confinement studies 16
3.1.6 Discussion: spectroscopic imaging of the pinwheel island ............ 21
3.1.7 Discussion: chirality of the spiral and the pinwheel......................... 23
3.1.8 Summary and outlook........................................................................ 24
3.2 Cu3Au(l 11) as a versatile platform for magnetic nano-graphenes................ 25
3.2.1 Introduction and summary................................................................. 25
3.2.2 Author’s contribution to the published work..................................... 27
4 Single-molecule magnetism and interactions with magnetic atoms 37
4.1 Spin on normal metal surfaces: Kondo effect.................................................. 38
4.1.1 Spectroscopic evidence of Kondo resonance..................................... 39
4.1.2 Zeeman effect........................................................................................ 40
4.2 Kondo-like feature of point defects on the herringbone phase PTCDA on Ag(lll)............................................................................................................ 41
4.2.1 Inelastic tunneling features................................................................ 41
4.2.2 Kondo-like feature at Fermi level .................................................... 44
4.3 Radical helicene molecules on metallic substrates........................................ 46
4.3.1 Helicenes on Au(l 11) substrate....................................................... 46
4.3.2 Magnetic field dependence of the zero bias resonance...................... 47
4.4 Nickelocene molecules with magnetic nano islands..................................... 52
4.4.1 Nickelocene on Cu(l 11).................................................................... 52
4.4.2 Magnetic properties of NiCp2 on cobalt islands............................... 54
4.5 Discussion and Outlook................................................................................... 58
5 Upgrading a low-temperature STM for electron spin resonance experiments 61
5.1 Introduction of ESR-STM ............................................................................. 61
5.2 Antenna installation for ESR measurements................................................. 63
5.3 Integration of RF into STM circuit................................................................. 64
5.4 Integration of magnetic field into the LT-STM.............................................. 67
5.4.1 Original plan...................................................................................... 68
5.4.2 A sacrificial magnet concept.............................................................. 69
5.5 Conclusion and outlook................................................................................... 75
6 Imaging PTCDA/Ag(lll) interface state with fast quasiparticle-interference mapping 77
6.1 Fast quasiparticle-interference mapping........................................................ 77
6.1.1 Quasiparticle interference mapping (QPI)........................................ 77
6.1.2 Fast quasiparticle interference mapping........................................... 79
6.1.3 Sparse sampling with piezoelectric creep........................................ 88
6.1.4 Summary and outlook...................................................................... 92
6.2 Imaging PTCDA/Ag(l 11) interface with sparse sampling method............... 93
6.2.1 Implement sparse sampling mapping on PTCDA/Ag(l 11)............ 93
6.2.2 Dispersion analysis............................................................................ 94
6.2.3 Comparison of two post-analysis methods........................................ 96
7 Instrumental developments of experimental setups 101
7.1 A strain device compatible with STM experiments.............................................103
7.1.1 Background of strain engineering.........................................................103
7.1.2 Design and commission of the strain device.........................................104
7.2 Updated dual sample holder design..................................................................... 106
7.3 Tip bombardment stage........................................................................................108
7.4 Accelerate the bake-out with exchange gas ..................................................... 109
7.5 Conclusion and outlook........................................................................................110
References 113

Abstract

Table of contents
1 Introduction 1
2 Scanning tunneling microscopy 3
2.1 Basics of scanning tunneling microscopy (STM)........................................... 3
2.2 Basics of scanning tunneling spectroscopy (STS)........................................ 4
2.2.1 Tersoff-Hamann Approximation........................................................ 4
2.2.2 Lock-in technique for di/dNmeasurement...................................... 5
2.2.3 Energy resolution in STS.................................................................... 6
3 Molecule growth on metallic surfaces 7
3.1 PTCDA mediated Ag(l 11) step edge faceting as a precursor of pinwheel phase 7
3.1.1 Pinwheel phase growth....................................................................... 7
3.1.2 Pinwheel structure analysis................................................................. 9
3.1.3 Electronic properties of the pinwheel phase..................................... 13
3.1.4 PTCDA decorated Ag( 111) step edge............................................... 14
3.1.5 Surface reconstruction as a template for quantum confinement studies 16
3.1.6 Discussion: spectroscopic imaging of the pinwheel island ............ 21
3.1.7 Discussion: chirality of the spiral and the pinwheel......................... 23
3.1.8 Summary and outlook........................................................................ 24
3.2 Cu3Au(l 11) as a versatile platform for magnetic nano-graphenes................ 25
3.2.1 Introduction and summary................................................................. 25
3.2.2 Author’s contribution to the published work..................................... 27
4 Single-molecule magnetism and interactions with magnetic atoms 37
4.1 Spin on normal metal surfaces: Kondo effect.................................................. 38
4.1.1 Spectroscopic evidence of Kondo resonance..................................... 39
4.1.2 Zeeman effect........................................................................................ 40
4.2 Kondo-like feature of point defects on the herringbone phase PTCDA on Ag(lll)............................................................................................................ 41
4.2.1 Inelastic tunneling features................................................................ 41
4.2.2 Kondo-like feature at Fermi level .................................................... 44
4.3 Radical helicene molecules on metallic substrates........................................ 46
4.3.1 Helicenes on Au(l 11) substrate....................................................... 46
4.3.2 Magnetic field dependence of the zero bias resonance...................... 47
4.4 Nickelocene molecules with magnetic nano islands..................................... 52
4.4.1 Nickelocene on Cu(l 11).................................................................... 52
4.4.2 Magnetic properties of NiCp2 on cobalt islands............................... 54
4.5 Discussion and Outlook................................................................................... 58
5 Upgrading a low-temperature STM for electron spin resonance experiments 61
5.1 Introduction of ESR-STM ............................................................................. 61
5.2 Antenna installation for ESR measurements................................................. 63
5.3 Integration of RF into STM circuit................................................................. 64
5.4 Integration of magnetic field into the LT-STM.............................................. 67
5.4.1 Original plan...................................................................................... 68
5.4.2 A sacrificial magnet concept.............................................................. 69
5.5 Conclusion and outlook................................................................................... 75
6 Imaging PTCDA/Ag(lll) interface state with fast quasiparticle-interference mapping 77
6.1 Fast quasiparticle-interference mapping........................................................ 77
6.1.1 Quasiparticle interference mapping (QPI)........................................ 77
6.1.2 Fast quasiparticle interference mapping........................................... 79
6.1.3 Sparse sampling with piezoelectric creep........................................ 88
6.1.4 Summary and outlook...................................................................... 92
6.2 Imaging PTCDA/Ag(l 11) interface with sparse sampling method............... 93
6.2.1 Implement sparse sampling mapping on PTCDA/Ag(l 11)............ 93
6.2.2 Dispersion analysis............................................................................ 94
6.2.3 Comparison of two post-analysis methods........................................ 96
7 Instrumental developments of experimental setups 101
7.1 A strain device compatible with STM experiments.............................................103
7.1.1 Background of strain engineering.........................................................103
7.1.2 Design and commission of the strain device.........................................104
7.2 Updated dual sample holder design..................................................................... 106
7.3 Tip bombardment stage........................................................................................108
7.4 Accelerate the bake-out with exchange gas ..................................................... 109
7.5 Conclusion and outlook........................................................................................110
References 113

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Additional indexing

Item Type:Dissertation (monographical)
Referees:Natterer Fabian Donat, Greber T, Gibert Marta
Communities & Collections:07 Faculty of Science > Physics Institute
UZH Dissertations
Dewey Decimal Classification:530 Physics
Language:English
Date:2023
Deposited On:19 Jan 2024 14:12
Last Modified:19 Jan 2024 14:12
Number of Pages:125
OA Status:Closed
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