University of Groningen
Connecting chirality and spin in electronic devices
Yang, Xu
DOI:
10.33612/diss.132019956
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Publication date: 2020
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Yang, X. (2020). Connecting chirality and spin in electronic devices. University of Groningen. https://doi.org/10.33612/diss.132019956
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Connecting chirality and spin in electronic devices
Xu Yang
2020
Zernike Institute PhD thesis series 2020-16 ISSN: 1570-1530 ISBN: 978-94-034-2894-9 (eBook) ISBN: 978-94-034-2895-6 (Book) c 2020 Xu Yang
The work described in this thesis was performed in the research group Physics of Nanodevices of the Zernike Institute for Advanced Materials at the University of Groningen, the Nether-lands. This work was supported by the Zernike Institute for Advanced Materials.
Cover art: The concepts of chirality and spin illustrated as a spiral and a spinning top. Cover design: Joanna Smolonska
Printed by: Lovebird design
Connecting chirality and spin in
electronic devices
PhD thesis
to obtain the degree of PhD at the University of Groningen
on the authority of the Rector Magnificus Prof. C. Wijmenga
and in accordance with the decision by the College of Deans. This thesis will be defended in public on Friday 18 September 2020 at 11.00 hours
by
Xu Yang
born on 26 November 1990 in Gansu, China
Zernike Institute PhD thesis series 2020-16 ISSN: 1570-1530 ISBN: 978-94-034-2894-9 (eBook) ISBN: 978-94-034-2895-6 (Book) c 2020 Xu Yang
The work described in this thesis was performed in the research group Physics of Nanodevices of the Zernike Institute for Advanced Materials at the University of Groningen, the Nether-lands. This work was supported by the Zernike Institute for Advanced Materials.
Cover art: The concepts of chirality and spin illustrated as a spiral and a spinning top. Cover design: Joanna Smolonska
Printed by: Lovebird design
Connecting chirality and spin in
electronic devices
PhD thesis
to obtain the degree of PhD at the University of Groningen
on the authority of the Rector Magnificus Prof. C. Wijmenga
and in accordance with the decision by the College of Deans. This thesis will be defended in public on Friday 18 September 2020 at 11.00 hours
by
Xu Yang
born on 26 November 1990 in Gansu, China
Supervisors
Prof. C.H. van der Wal Prof. B.J. van Wees
Assessment Committee
Prof. B.L. Feringa Prof. H.S.J. van der Zant Prof. H.M. Yamamoto
Supervisors
Prof. C.H. van der Wal Prof. B.J. van Wees
Assessment Committee
Prof. B.L. Feringa Prof. H.S.J. van der Zant Prof. H.M. Yamamoto
Contents
1 Introduction – Unraveling chirality-induced spin selectivity (CISS) 1
1.1 Nature is chiral . . . 2
1.2 A spintronics vision for the future . . . 3
1.3 The rise of CISS . . . 3
1.4 Open questions . . . 6
1.5 This thesis . . . 6
1.6 Guideline to readers . . . 7
Bibliography . . . 8
2 A symmetry perspective of chirality, spin, and CISS 13 2.1 Symmetry and chirality . . . 14
2.1.1 Molecular symmetry operations . . . 14
2.1.2 Fundamental symmetries of space and time . . . 16
2.1.3 True chirality . . . 17
2.2 Spin-related symmetry implications . . . 18
2.2.1 The Kramers degeneracy theorem . . . 18
2.2.2 Symmetry restrictions on electronic energy band . . . 19
2.2.3 Spin–charge conversion by symmetry breaking . . . 19
2.2.4 The Onsager reciprocity . . . 22
2.3 Chirality-induced physical phenomena . . . 23
2.3.1 Optical rotation and circular dichroism . . . 23
2.3.2 Generalized helicity-induced dichroism . . . 24
2.3.3 Magnetochiral effects . . . 25
2.4 CISS experiments revisited . . . 26
2.4.1 Photoemission experiments . . . 26
2.4.2 Magnetotransport experiments . . . 26 vii
Contents
1 Introduction – Unraveling chirality-induced spin selectivity (CISS) 1
1.1 Nature is chiral . . . 2
1.2 A spintronics vision for the future . . . 3
1.3 The rise of CISS . . . 3
1.4 Open questions . . . 6
1.5 This thesis . . . 6
1.6 Guideline to readers . . . 7
Bibliography . . . 8
2 A symmetry perspective of chirality, spin, and CISS 13 2.1 Symmetry and chirality . . . 14
2.1.1 Molecular symmetry operations . . . 14
2.1.2 Fundamental symmetries of space and time . . . 16
2.1.3 True chirality . . . 17
2.2 Spin-related symmetry implications . . . 18
2.2.1 The Kramers degeneracy theorem . . . 18
2.2.2 Symmetry restrictions on electronic energy band . . . 19
2.2.3 Spin–charge conversion by symmetry breaking . . . 19
2.2.4 The Onsager reciprocity . . . 22
2.3 Chirality-induced physical phenomena . . . 23
2.3.1 Optical rotation and circular dichroism . . . 23
2.3.2 Generalized helicity-induced dichroism . . . 24
2.3.3 Magnetochiral effects . . . 25
2.4 CISS experiments revisited . . . 26
2.4.1 Photoemission experiments . . . 26
2.4.2 Magnetotransport experiments . . . 26 vii
Contents
2.4.3 The role of substrate . . . 27
2.5 Appendices . . . 28
Bibliography . . . 32
3 Spin-dependent electron transmission model for chiral molecules in meso-scopic devices 39 3.1 An electron transmission model for chiral molecules . . . 41
3.1.1 Reciprocity theorem and spin-flip reflection by chiral molecules 42 3.1.2 Matrix formalism and barrier-CISS center-barrier (BCB) model for CISS molecules . . . 44
3.2 Discussion . . . 46
3.2.1 Two-terminal geometries . . . 46
3.2.2 Four-terminal geometries and experimental designs . . . 49
3.3 Conclusion . . . 55
3.4 Reply to Comment . . . 56
3.5 Appendices . . . 60
Bibliography . . . 70
4 Detecting chirality in two-terminal electronic nanodevices 73 4.1 Transport matrix formalism beyond Landauer formula . . . 74
4.1.1 Spin–charge conversion in a chiral component . . . 75
4.1.2 Spin–charge conversion in a magnetic tunnel junction . . . 77
4.2 Origin of MR – energy-dependent transport and energy relaxation . . 77
4.2.1 No MR in the linear response regime . . . 77
4.2.2 Emergence of MR in nonlinear regime . . . 79
4.3 Chiral spin valve . . . 82
4.4 Discussion . . . 84
4.5 Appendices . . . 84
Bibliography . . . 96
5 Circuit-model analysis for spintronic devices with chiral molecules as spin injectors 99 5.1 Circuit-model analysis . . . 100 5.2 Discussion . . . 105 5.3 Conclusion . . . 107 5.4 Appendices . . . 108 Bibliography . . . 111 viii Contents 6 Highly anisotropic and nonreciprocal charge transport in chiral van der Waals Tellurium 115 6.1 Highly anisotropic charge transport in Tellurene . . . 116
6.1.1 Angle-resolved mesoscopic conductance . . . 116
6.1.2 Inhomogeneity and chirality effects in 2D conduction . . . 119
6.1.3 Anisotropic temperature dependence . . . 121
6.2 Nonreciprocal charge transport in Tellurene . . . 122
6.2.1 Bias dependence of nonlinear charge transport . . . 122
6.2.2 Discussion on nonlinear mechanisms . . . 123
6.3 Conclusion . . . 124
6.4 Methods . . . 125
6.5 Appendices . . . 126
Bibliography . . . 129
7 Enhancing and rectifying electron transport through a biomolecular junc-tion comprising Photosystem I and graphene 133 7.1 Binding PSI onto graphene using peptides . . . 134
7.1.1 Sample preparation . . . 134
7.1.2 Peptide improves PSI coverage . . . 135
7.2 Enhanced and rectified PSI-graphene electron transport . . . 137
7.2.1 Point-and-shoot technique for I-V characterization . . . 137
7.2.2 Random positioning method for statistical confirmation . . . . 139
7.3 Mechanical tuning of PSI-graphene electron transport . . . 140
7.4 Conclusion . . . 143
7.5 Methods . . . 143
Bibliography . . . 144
8 Closing remark – Spinchiraltronics 147 8.1 Conclusion . . . 148 8.2 Further questions . . . 150 8.3 Outlook – Spinchiraltronics . . . 151 Summary 153 Samenvatting 158 Acknowledgements 164 Publications 171 Curriculum Vitae 173 ix
Contents
2.4.3 The role of substrate . . . 27
2.5 Appendices . . . 28
Bibliography . . . 32
3 Spin-dependent electron transmission model for chiral molecules in meso-scopic devices 39 3.1 An electron transmission model for chiral molecules . . . 41
3.1.1 Reciprocity theorem and spin-flip reflection by chiral molecules 42 3.1.2 Matrix formalism and barrier-CISS center-barrier (BCB) model for CISS molecules . . . 44
3.2 Discussion . . . 46
3.2.1 Two-terminal geometries . . . 46
3.2.2 Four-terminal geometries and experimental designs . . . 49
3.3 Conclusion . . . 55
3.4 Reply to Comment . . . 56
3.5 Appendices . . . 60
Bibliography . . . 70
4 Detecting chirality in two-terminal electronic nanodevices 73 4.1 Transport matrix formalism beyond Landauer formula . . . 74
4.1.1 Spin–charge conversion in a chiral component . . . 75
4.1.2 Spin–charge conversion in a magnetic tunnel junction . . . 77
4.2 Origin of MR – energy-dependent transport and energy relaxation . . 77
4.2.1 No MR in the linear response regime . . . 77
4.2.2 Emergence of MR in nonlinear regime . . . 79
4.3 Chiral spin valve . . . 82
4.4 Discussion . . . 84
4.5 Appendices . . . 84
Bibliography . . . 96
5 Circuit-model analysis for spintronic devices with chiral molecules as spin injectors 99 5.1 Circuit-model analysis . . . 100 5.2 Discussion . . . 105 5.3 Conclusion . . . 107 5.4 Appendices . . . 108 Bibliography . . . 111 viii Contents 6 Highly anisotropic and nonreciprocal charge transport in chiral van der Waals Tellurium 115 6.1 Highly anisotropic charge transport in Tellurene . . . 116
6.1.1 Angle-resolved mesoscopic conductance . . . 116
6.1.2 Inhomogeneity and chirality effects in 2D conduction . . . 119
6.1.3 Anisotropic temperature dependence . . . 121
6.2 Nonreciprocal charge transport in Tellurene . . . 122
6.2.1 Bias dependence of nonlinear charge transport . . . 122
6.2.2 Discussion on nonlinear mechanisms . . . 123
6.3 Conclusion . . . 124
6.4 Methods . . . 125
6.5 Appendices . . . 126
Bibliography . . . 129
7 Enhancing and rectifying electron transport through a biomolecular junc-tion comprising Photosystem I and graphene 133 7.1 Binding PSI onto graphene using peptides . . . 134
7.1.1 Sample preparation . . . 134
7.1.2 Peptide improves PSI coverage . . . 135
7.2 Enhanced and rectified PSI-graphene electron transport . . . 137
7.2.1 Point-and-shoot technique for I-V characterization . . . 137
7.2.2 Random positioning method for statistical confirmation . . . . 139
7.3 Mechanical tuning of PSI-graphene electron transport . . . 140
7.4 Conclusion . . . 143
7.5 Methods . . . 143
Bibliography . . . 144
8 Closing remark – Spinchiraltronics 147 8.1 Conclusion . . . 148 8.2 Further questions . . . 150 8.3 Outlook – Spinchiraltronics . . . 151 Summary 153 Samenvatting 158 Acknowledgements 164 Publications 171 Curriculum Vitae 173 ix
