Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array

Liuyang Sun, Chun Yuan Wang, Alex Krasnok, Junho Choi, Jinwei Shi, Juan Sebastian Gomez Diaz, André Zepeda, Shangjr Gwo, Chih Kang Shih, Andrea Alù, Xiaoqin Li

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Excitons in monolayer transition metal dichalcogenides are formed at K and K′ points at the boundary of the Brillouin zone. They acquire a valley degree of freedom, which has been explored as an alternative information carrier, analogous to charge or spin. Two opposite valleys in transition metal dichalcogenides can be optically addressed using light with different helicity. Here, we demonstrate that valley-polarized excitons can be sorted and spatially separated at room temperature by coupling a MoS 2 monolayer to a subwavelength asymmetric groove array. In addition to separation of valley excitons in real space, emission from valley excitons is also separated in photon momentum-space; that is, the helicity of photons determines a preferential emission direction. Our work demonstrates that metasurfaces can facilitate valley transport and establish an interface between valleytronic and photonic devices, thus addressing outstanding challenges in the field of valleytronics.

Original languageEnglish (US)
Pages (from-to)180-184
Number of pages5
JournalNature Photonics
Volume13
Issue number3
DOIs
StatePublished - Mar 1 2019

Fingerprint

Excitons
grooves
valleys
Monolayers
excitons
Transition metals
Photons
Photonic devices
transition metals
Momentum
photons
Brillouin zones
LDS 751
degrees of freedom
photonics
momentum
room temperature
Temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

Cite this

Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array . / Sun, Liuyang; Wang, Chun Yuan; Krasnok, Alex; Choi, Junho; Shi, Jinwei; Gomez Diaz, Juan Sebastian; Zepeda, André; Gwo, Shangjr; Shih, Chih Kang; Alù, Andrea; Li, Xiaoqin.

In: Nature Photonics, Vol. 13, No. 3, 01.03.2019, p. 180-184.

Research output: Contribution to journalArticle

Sun, L, Wang, CY, Krasnok, A, Choi, J, Shi, J, Gomez Diaz, JS, Zepeda, A, Gwo, S, Shih, CK, Alù, A & Li, X 2019, ' Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array ', Nature Photonics, vol. 13, no. 3, pp. 180-184. https://doi.org/10.1038/s41566-019-0348-z
Sun, Liuyang ; Wang, Chun Yuan ; Krasnok, Alex ; Choi, Junho ; Shi, Jinwei ; Gomez Diaz, Juan Sebastian ; Zepeda, André ; Gwo, Shangjr ; Shih, Chih Kang ; Alù, Andrea ; Li, Xiaoqin. / Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array In: Nature Photonics. 2019 ; Vol. 13, No. 3. pp. 180-184.
@article{8fb70bd3f51e48f4b5a9f341f5fd75dc,
title = "Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array",
abstract = "Excitons in monolayer transition metal dichalcogenides are formed at K and K′ points at the boundary of the Brillouin zone. They acquire a valley degree of freedom, which has been explored as an alternative information carrier, analogous to charge or spin. Two opposite valleys in transition metal dichalcogenides can be optically addressed using light with different helicity. Here, we demonstrate that valley-polarized excitons can be sorted and spatially separated at room temperature by coupling a MoS 2 monolayer to a subwavelength asymmetric groove array. In addition to separation of valley excitons in real space, emission from valley excitons is also separated in photon momentum-space; that is, the helicity of photons determines a preferential emission direction. Our work demonstrates that metasurfaces can facilitate valley transport and establish an interface between valleytronic and photonic devices, thus addressing outstanding challenges in the field of valleytronics.",
author = "Liuyang Sun and Wang, {Chun Yuan} and Alex Krasnok and Junho Choi and Jinwei Shi and {Gomez Diaz}, {Juan Sebastian} and Andr{\'e} Zepeda and Shangjr Gwo and Shih, {Chih Kang} and Andrea Al{\`u} and Xiaoqin Li",
year = "2019",
month = "3",
day = "1",
doi = "10.1038/s41566-019-0348-z",
language = "English (US)",
volume = "13",
pages = "180--184",
journal = "Nature Photonics",
issn = "1749-4885",
publisher = "Nature Publishing Group",
number = "3",

}

TY - JOUR

T1 - Separation of valley excitons in a MoS 2 monolayer using a subwavelength asymmetric groove array

AU - Sun, Liuyang

AU - Wang, Chun Yuan

AU - Krasnok, Alex

AU - Choi, Junho

AU - Shi, Jinwei

AU - Gomez Diaz, Juan Sebastian

AU - Zepeda, André

AU - Gwo, Shangjr

AU - Shih, Chih Kang

AU - Alù, Andrea

AU - Li, Xiaoqin

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Excitons in monolayer transition metal dichalcogenides are formed at K and K′ points at the boundary of the Brillouin zone. They acquire a valley degree of freedom, which has been explored as an alternative information carrier, analogous to charge or spin. Two opposite valleys in transition metal dichalcogenides can be optically addressed using light with different helicity. Here, we demonstrate that valley-polarized excitons can be sorted and spatially separated at room temperature by coupling a MoS 2 monolayer to a subwavelength asymmetric groove array. In addition to separation of valley excitons in real space, emission from valley excitons is also separated in photon momentum-space; that is, the helicity of photons determines a preferential emission direction. Our work demonstrates that metasurfaces can facilitate valley transport and establish an interface between valleytronic and photonic devices, thus addressing outstanding challenges in the field of valleytronics.

AB - Excitons in monolayer transition metal dichalcogenides are formed at K and K′ points at the boundary of the Brillouin zone. They acquire a valley degree of freedom, which has been explored as an alternative information carrier, analogous to charge or spin. Two opposite valleys in transition metal dichalcogenides can be optically addressed using light with different helicity. Here, we demonstrate that valley-polarized excitons can be sorted and spatially separated at room temperature by coupling a MoS 2 monolayer to a subwavelength asymmetric groove array. In addition to separation of valley excitons in real space, emission from valley excitons is also separated in photon momentum-space; that is, the helicity of photons determines a preferential emission direction. Our work demonstrates that metasurfaces can facilitate valley transport and establish an interface between valleytronic and photonic devices, thus addressing outstanding challenges in the field of valleytronics.

UR - http://www.scopus.com/inward/record.url?scp=85061491586&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85061491586&partnerID=8YFLogxK

U2 - 10.1038/s41566-019-0348-z

DO - 10.1038/s41566-019-0348-z

M3 - Article

AN - SCOPUS:85061491586

VL - 13

SP - 180

EP - 184

JO - Nature Photonics

JF - Nature Photonics

SN - 1749-4885

IS - 3

ER -