Strong-coupling charge density wave in monolayer TiSe2

Matthew D Watson; Akhil Rajan; Tommaso Antonelli; Kaycee Underwood; Igor Marković; Federico Mazzola; Oliver Jon Clark; Gesa-Roxanne Siemann; Deepnarayanan Biswas; Andrew Hunter; Sven Jandura; Janika Reichstetter; Martin Mclaren; Patrick Le Fèvre; Giovanni Vinai; Philip D C King

doi:10.1088/2053-1583/abafec

Strong-coupling charge density wave in monolayer TiSe₂

Matthew D Watson^*, Akhil Rajan, Tommaso Antonelli, Kaycee Underwood, Igor Marković, Federico Mazzola, Oliver Jon Clark, Gesa-Roxanne Siemann, Deepnarayanan Biswas, Andrew Hunter, Sven Jandura, Janika Reichstetter, Martin Mclaren, Patrick Le Fèvre, Giovanni Vinai, Philip D C King^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

We study the 2×2 charge density wave (CDW) in epitaxially-grown monolayer TiSe₂. Our temperature-dependent angle-resolved photoemission spectroscopy measurements indicate a strong-coupling instability, but reveal how not all states couple equally to the symmetry-breaking distortion, with an electron pocket persisting to low temperature as a non-bonding state. We further show how the CDW order can be suppressed by a modest doping of around 0.06(2) electrons per Ti. Our results provide an opportunity for quantitative comparison with a realistic tight-binding model, which emphasises a crucial role of structural aspects of the phase transition in understanding the hybridisation in the ground state. Together, our work provides a comprehensive understanding of the phenomenology of the CDW in TiSe₂ in the 2D limit.

Original language	English
Article number	015004
Number of pages	10
Journal	2D Materials
Volume	8
Issue number	1
DOIs	https://doi.org/10.1088/2053-1583/abafec
Publication status	Published - 12 Oct 2020

Keywords

ARPES
CDW
Monolayer
TiSe2MBE
Transition metal dichalcogenides

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10.1088/2053-1583/abafec

Watson_2020_2DM_Strong-coupling_AAM
Copyright © 2020 IOP Publishing Ltd. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1088/2053-1583/abafec
Accepted author manuscript, 7.94 MBLicence: CC BY-NC-ND

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@article{3ca8054dc6d04d98a158cce737e93ad0,

title = "Strong-coupling charge density wave in monolayer TiSe2",

abstract = "We study the 2×2 charge density wave (CDW) in epitaxially-grown monolayer TiSe2. Our temperature-dependent angle-resolved photoemission spectroscopy measurements indicate a strong-coupling instability, but reveal how not all states couple equally to the symmetry-breaking distortion, with an electron pocket persisting to low temperature as a non-bonding state. We further show how the CDW order can be suppressed by a modest doping of around 0.06(2) electrons per Ti. Our results provide an opportunity for quantitative comparison with a realistic tight-binding model, which emphasises a crucial role of structural aspects of the phase transition in understanding the hybridisation in the ground state. Together, our work provides a comprehensive understanding of the phenomenology of the CDW in TiSe2 in the 2D limit. ",

keywords = "ARPES, CDW, Monolayer, TiSe2MBE, Transition metal dichalcogenides",

author = "Watson, \{Matthew D\} and Akhil Rajan and Tommaso Antonelli and Kaycee Underwood and Igor Markovi{\'c} and Federico Mazzola and Clark, \{Oliver Jon\} and Gesa-Roxanne Siemann and Deepnarayanan Biswas and Andrew Hunter and Sven Jandura and Janika Reichstetter and Martin Mclaren and \{Le F{\`e}vre\}, Patrick and Giovanni Vinai and King, \{Philip D C\}",

note = "Funding: Authors gratefully acknowledge funding from The Royal Society, The Leverhulme Trust, and the European Research Council (through the ERC-714193-QUESTDO project). The MBE growth facility was funded through the Engineering and Physical Sciences Research Council (EPSRC) under Grant No. EP/M023958/1. KU and OJC acknowledge the EPSRC for PhD studentship support via Grant Nos. EP/L015110/1 and EP/K503162/1, and IM the International Max Planck Research School for Chemistry and Physics of Quantum Materials. We thank SOLEIL synchrotron for access to the CASSIOPEE beamline (proposal 20171202) and Elettra synchrotron for access to the APE-HE beamline, which both contributed to the results presented here. This work has been partially performed in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MIUR Italy Progetti Internazionali) facility. The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.",

year = "2020",

month = oct,

day = "12",

doi = "10.1088/2053-1583/abafec",

language = "English",

volume = "8",

journal = "2D Materials",

issn = "2053-1583",

publisher = "IOP Publishing Ltd.",

number = "1",

}

TY - JOUR

T1 - Strong-coupling charge density wave in monolayer TiSe2

AU - Watson, Matthew D

AU - Rajan, Akhil

AU - Antonelli, Tommaso

AU - Underwood, Kaycee

AU - Marković, Igor

AU - Mazzola, Federico

AU - Clark, Oliver Jon

AU - Siemann, Gesa-Roxanne

AU - Biswas, Deepnarayanan

AU - Hunter, Andrew

AU - Jandura, Sven

AU - Reichstetter, Janika

AU - Mclaren, Martin

AU - Le Fèvre, Patrick

AU - Vinai, Giovanni

AU - King, Philip D C

N1 - Funding: Authors gratefully acknowledge funding from The Royal Society, The Leverhulme Trust, and the European Research Council (through the ERC-714193-QUESTDO project). The MBE growth facility was funded through the Engineering and Physical Sciences Research Council (EPSRC) under Grant No. EP/M023958/1. KU and OJC acknowledge the EPSRC for PhD studentship support via Grant Nos. EP/L015110/1 and EP/K503162/1, and IM the International Max Planck Research School for Chemistry and Physics of Quantum Materials. We thank SOLEIL synchrotron for access to the CASSIOPEE beamline (proposal 20171202) and Elettra synchrotron for access to the APE-HE beamline, which both contributed to the results presented here. This work has been partially performed in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MIUR Italy Progetti Internazionali) facility. The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.

PY - 2020/10/12

Y1 - 2020/10/12

N2 - We study the 2×2 charge density wave (CDW) in epitaxially-grown monolayer TiSe2. Our temperature-dependent angle-resolved photoemission spectroscopy measurements indicate a strong-coupling instability, but reveal how not all states couple equally to the symmetry-breaking distortion, with an electron pocket persisting to low temperature as a non-bonding state. We further show how the CDW order can be suppressed by a modest doping of around 0.06(2) electrons per Ti. Our results provide an opportunity for quantitative comparison with a realistic tight-binding model, which emphasises a crucial role of structural aspects of the phase transition in understanding the hybridisation in the ground state. Together, our work provides a comprehensive understanding of the phenomenology of the CDW in TiSe2 in the 2D limit.

AB - We study the 2×2 charge density wave (CDW) in epitaxially-grown monolayer TiSe2. Our temperature-dependent angle-resolved photoemission spectroscopy measurements indicate a strong-coupling instability, but reveal how not all states couple equally to the symmetry-breaking distortion, with an electron pocket persisting to low temperature as a non-bonding state. We further show how the CDW order can be suppressed by a modest doping of around 0.06(2) electrons per Ti. Our results provide an opportunity for quantitative comparison with a realistic tight-binding model, which emphasises a crucial role of structural aspects of the phase transition in understanding the hybridisation in the ground state. Together, our work provides a comprehensive understanding of the phenomenology of the CDW in TiSe2 in the 2D limit.

KW - ARPES

KW - CDW

KW - Monolayer

KW - TiSe2MBE

KW - Transition metal dichalcogenides

UR - https://www.scopus.com/pages/publications/85094861951

U2 - 10.1088/2053-1583/abafec

DO - 10.1088/2053-1583/abafec

M3 - Article

SN - 2053-1583

VL - 8

JO - 2D Materials

JF - 2D Materials

IS - 1

M1 - 015004

ER -

Strong-coupling charge density wave in monolayer TiSe₂

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RS Phil King: Electronic Structure Engineering of Novel Topological Phases

Engineered Quantum States: Engineered quantum states via atmoic-scale assembly of artificial 2D heterostructures

ERC Starting Grant QUESTDO: H2020 ERC Starting Grant QUESTDO