Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Tuomas P. Rossi; Kirsten T. Winther; Karsten W. Jacobsen; Risto M. Nieminen; Martti J. Puska; Kristian S. Thygesen

doi:10.1103/PhysRevB.96.155407

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

Tuomas P. Rossi^*, Kirsten T. Winther, Karsten W. Jacobsen, Risto M. Nieminen, Martti J. Puska, Kristian S. Thygesen

^*Corresponding author for this work

Department of Applied Physics

Technical University of Denmark

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

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Abstract

Finite MoS2 nanoparticles are known to support metallic edge states that are responsible for their catalytic activity. In this work we employ time-dependent density-functional theory (TDDFT) to study the influence of such edge states on the optical properties of triangular MoS2 monolayer flakes. We find that the edge states support collective plasmon-like excitations that couple strongly to the optical field leading to pronounced absorption peaks below the onset of interband transitions on the basal plane. Additionally, structural relaxation of the flakes can significantly distort the edge states. Thus, we observe that while an evenly-spaced edge configuration supports one-dimensional (1D) plasmon modes similar to those of an ideal 1D electron gas, the relaxed structures show mixed plasmon and single-electron excitations in the low-energy response. Our findings illustrate the sensitivity of the optical response of MoS2 nanostructures to the details of the edge configuration.

Original language	English
Article number	155407
Number of pages	10
Journal	Physical Review B
Volume	96
Issue number	15
DOIs	https://doi.org/10.1103/PhysRevB.96.155407
Publication status	Published - 5 Oct 2017
MoE publication type	A1 Journal article-refereed

Funding

We thank the Academy of Finland for support through its Centres of Excellence Programme (2012-2017) under Projects No. 251748 and No. 284621. The Center for Nanostructured Graphene (CNG) is sponsored by the Danish National Research Foundation, Project No. DNRF103. T.P.R. thanks the Vilho, Yrjo, and Kalle Vaisala Foundation of the Finnish Academy of Science and Letters and the Finnish Cultural Foundation for support. We acknowledge computational resources provided by CSC - IT Center for Science (Finland), the Aalto Science-IT project (Aalto University School of Science), and the Niflheim supercomputer (Technical University of Denmark). The NumPy [67] and Matplotlib [68] Python packages and the VMD software [69,70] were used for processing the data and generating the figures.

Keywords

DER-WAALS HETEROSTRUCTURES
ELECTRONIC-STRUCTURE
NANOCLUSTERS
APPROXIMATION
NANOPARTICLES
GRAPHENE
SITES
NANOSTRUCTURES
SYSTEMS
SIZE

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10.1103/PhysRevB.96.155407

PhysRevB.96.155407-1Final published version, 1.54 MB

Cite this

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title = "Effect of edge plasmons on the optical properties of MoS2 monolayer flakes",

abstract = "Finite MoS2 nanoparticles are known to support metallic edge states that are responsible for their catalytic activity. In this work we employ time-dependent density-functional theory (TDDFT) to study the influence of such edge states on the optical properties of triangular MoS2 monolayer flakes. We find that the edge states support collective plasmon-like excitations that couple strongly to the optical field leading to pronounced absorption peaks below the onset of interband transitions on the basal plane. Additionally, structural relaxation of the flakes can significantly distort the edge states. Thus, we observe that while an evenly-spaced edge configuration supports one-dimensional (1D) plasmon modes similar to those of an ideal 1D electron gas, the relaxed structures show mixed plasmon and single-electron excitations in the low-energy response. Our findings illustrate the sensitivity of the optical response of MoS2 nanostructures to the details of the edge configuration.",

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author = "Rossi, \{Tuomas P.\} and Winther, \{Kirsten T.\} and Jacobsen, \{Karsten W.\} and Nieminen, \{Risto M.\} and Puska, \{Martti J.\} and Thygesen, \{Kristian S.\}",

year = "2017",

month = oct,

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doi = "10.1103/PhysRevB.96.155407",

language = "English",

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AU - Rossi, Tuomas P.

AU - Winther, Kirsten T.

AU - Jacobsen, Karsten W.

AU - Nieminen, Risto M.

AU - Puska, Martti J.

AU - Thygesen, Kristian S.

PY - 2017/10/5

Y1 - 2017/10/5

N2 - Finite MoS2 nanoparticles are known to support metallic edge states that are responsible for their catalytic activity. In this work we employ time-dependent density-functional theory (TDDFT) to study the influence of such edge states on the optical properties of triangular MoS2 monolayer flakes. We find that the edge states support collective plasmon-like excitations that couple strongly to the optical field leading to pronounced absorption peaks below the onset of interband transitions on the basal plane. Additionally, structural relaxation of the flakes can significantly distort the edge states. Thus, we observe that while an evenly-spaced edge configuration supports one-dimensional (1D) plasmon modes similar to those of an ideal 1D electron gas, the relaxed structures show mixed plasmon and single-electron excitations in the low-energy response. Our findings illustrate the sensitivity of the optical response of MoS2 nanostructures to the details of the edge configuration.

AB - Finite MoS2 nanoparticles are known to support metallic edge states that are responsible for their catalytic activity. In this work we employ time-dependent density-functional theory (TDDFT) to study the influence of such edge states on the optical properties of triangular MoS2 monolayer flakes. We find that the edge states support collective plasmon-like excitations that couple strongly to the optical field leading to pronounced absorption peaks below the onset of interband transitions on the basal plane. Additionally, structural relaxation of the flakes can significantly distort the edge states. Thus, we observe that while an evenly-spaced edge configuration supports one-dimensional (1D) plasmon modes similar to those of an ideal 1D electron gas, the relaxed structures show mixed plasmon and single-electron excitations in the low-energy response. Our findings illustrate the sensitivity of the optical response of MoS2 nanostructures to the details of the edge configuration.

KW - DER-WAALS HETEROSTRUCTURES

KW - ELECTRONIC-STRUCTURE

KW - NANOCLUSTERS

KW - APPROXIMATION

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KW - GRAPHENE

KW - SITES

KW - NANOSTRUCTURES

KW - SYSTEMS

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VL - 96

JO - Physical Review B

JF - Physical Review B

IS - 15

M1 - 155407

ER -

Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

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Effect of edge plasmons on the optical properties of MoS2 monolayer flakes

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Science-IT

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