Valley-selective directional emission from a transition-metal dichalcogenide monolayer mediated by a plasmonic nanoantenna

Background: Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) with intrinsically crystal inversion-symmetry breaking have shown many advanced optical properties. In particular, the valley polarization in 2D TMDCs that can be addressed optically has inspired new physical phenomena and great potential applications in valleytronics. Results: Here, we propose a TMDC–nanoantenna system that could effectively enhance and direct emission from the two valleys in TMDCs into diametrically opposite directions. By mimicking the emission from each valley of the monolayer of WSe2 as a chiral point-dipole emitter, we demonstrate numerically that the emission from different valleys is directed into opposite directions when coupling to a double-bar plasmonic nanoantenna. The directionality derives from the interference between the dipole and quadrupole modes excited in the two bars, respectively. Thus, we could tune the emission direction from the proposed TMDC–nanoantenna system by tuning the pumping without changing the antenna structure. Furthermore, we discuss the general principles and the opportunities to improve the average performance of the nanoantenna structure. Conclusion: The scheme we propose here can potentially serve as an important component for valley-based applications, such as non-volatile information storage and processing.

[1]  Stuart A. Wolf,et al.  Spintronics : A Spin-Based Electronics Vision for the Future , 2009 .

[2]  A. Rauschenbeutel,et al.  Quantum state-controlled directional spontaneous emission of photons into a nanophotonic waveguide , 2014, Nature Communications.

[3]  P. Guyot-Sionnest,et al.  Excitation of dark plasmons in metal nanoparticles by a localized emitter. , 2009, Physical review letters.

[4]  Y. Kivshar,et al.  Spin-Polarized Photon Emission by Resonant Multipolar Nanoantennas , 2014 .

[5]  M. Shayegan,et al.  Valley splitting of AlAs two-dimensional electrons in a perpendicular magnetic field. , 2002, Physical review letters.

[6]  Keliang He,et al.  Control of valley polarization in monolayer MoS2 by optical helicity. , 2012, Nature nanotechnology.

[7]  J. Shan,et al.  Atomically thin MoS₂: a new direct-gap semiconductor. , 2010, Physical review letters.

[8]  Peter Zoller,et al.  Chiral quantum optics , 2016, Nature.

[9]  F. J. Rodríguez-Fortuño,et al.  Near-Field Interference for the Unidirectional Excitation of Electromagnetic Guided Modes , 2013, Science.

[10]  Chennupati Jagadish,et al.  Dual-channel spontaneous emission of quantum dots in magnetic metamaterials , 2013, Nature Communications.

[11]  Keliang He,et al.  Orientation of luminescent excitons in layered nanomaterials. , 2013, Nature nanotechnology.

[12]  Boris N. Chichkov,et al.  Multipole light scattering by nonspherical nanoparticles in the discrete dipole approximation , 2011 .

[13]  Giorgio Volpe,et al.  Multipolar radiation of quantum emitters with nanowire optical antennas , 2013, Nature Communications.

[14]  Wang Yao,et al.  Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. , 2011, Physical review letters.

[15]  R. W. Christy,et al.  Optical Constants of the Noble Metals , 1972 .

[16]  Vahid Sandoghdar,et al.  Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna. , 2006, Physical review letters.

[17]  B. Jonker,et al.  Exciton diamagnetic shifts and valley Zeeman effects in monolayer WS2 and MoS2 to 65 Tesla , 2015, Nature Communications.

[18]  Rajesh R Naik,et al.  Nanomanufacturing of 2D Transition Metal Dichalcogenide Materials Using Self-Assembled DNA Nanotubes. , 2015, Small.

[19]  Zongfu Yu,et al.  Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna , 2009 .

[20]  Wang Yao,et al.  Valley polarization in MoS2 monolayers by optical pumping. , 2012, Nature nanotechnology.

[21]  Ji Feng,et al.  Valley-selective circular dichroism of monolayer molybdenum disulphide , 2012, Nature Communications.

[22]  L. Kuipers,et al.  Nanophotonic control of circular dipole emission , 2015, Nature Communications.

[23]  Marta Castro-López,et al.  Multipolar interference for directed light emission. , 2014, Nano letters.

[24]  Y. Uemura,et al.  Theory of Valley Splitting in an N-Channel (100) Inversion Layer of Si III. Enhancement of Splittings by Many-Body Effects , 1977 .

[25]  R. Asgari,et al.  Valley Zeeman effect and spin-valley polarized conductance in monolayerMoS2in a perpendicular magnetic field , 2014, 1412.1459.

[26]  Xu Cui,et al.  Valley splitting and polarization by the Zeeman effect in monolayer MoSe2. , 2014, Physical Review Letters.

[27]  Aaron M. Jones,et al.  Supplementary Materials Magnetic Control of Valley Pseudospin in Monolayer WSe2 , 2014, 1407.2645.

[28]  M. Koperski,et al.  Tuning Valley Polarization in a WSe 2 Monolayer with a Tiny Magnetic Field , 2015, 1512.00839.

[29]  Wang Yao,et al.  Spin and pseudospins in layered transition metal dichalcogenides , 2014, Nature Physics.

[30]  Hai Xu,et al.  Controlled Growth of 1D MoSe2 Nanoribbons with Spatially Modulated Edge States. , 2017, Nano letters.

[31]  D. A. Dunnett.  Classical Electrodynamics , 2020, Nature.

[32]  Tony F. Heinz,et al.  Optical manipulation of valley pseudospin , 2016, Nature Physics.

[33]  Tuo-Hung Hou,et al.  Optically initialized robust valley-polarized holes in monolayer WSe2 , 2015, Nature Communications.

[34]  Andras Kis,et al.  Valley Zeeman effect in elementary optical excitations of monolayer WSe2 , 2014, Nature Physics.

[35]  T. Klar,et al.  Shaping emission spectra of fluorescent molecules with single plasmonic nanoresonators. , 2008, Physical review letters.

[36]  F. Nori,et al.  Quantum spin Hall effect of light , 2015, Science.

[37]  Y. J. Zhang,et al.  Electrically Switchable Chiral Light-Emitting Transistor , 2014, Science.

[38]  J. Shan,et al.  Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides , 2016, Nature Photonics.

[39]  Madan Dubey,et al.  Two-dimensional material nanophotonics , 2014, 1410.3882.

[40]  Qing Hua Wang,et al.  Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. , 2012, Nature nanotechnology.

[41]  Aaron M. Jones,et al.  Optical generation of excitonic valley coherence in monolayer WSe2. , 2013, Nature nanotechnology.

[42]  Breaking the symmetry of forward-backward light emission with localized and collective magnetoelectric resonances in arrays of pyramid-shaped aluminum nanoparticles. , 2014, Physical review letters.

[43]  L. Novotný,et al.  Enhancement and quenching of single-molecule fluorescence. , 2006, Physical review letters.

[44]  Valley- and spin-polarized Landau levels in monolayer WSe2. , 2017, Nature nanotechnology.

[45]  C. W. J. Beenakker,et al.  Valley filter and valley valve in graphene , 2007 .

[46]  P. L. McEuen,et al.  The valley Hall effect in MoS2 transistors , 2014, Science.

[47]  Aaron M. Jones,et al.  Electrical tuning of valley magnetic moment through symmetry control in bilayer MoS2 , 2012, 1208.6069.

[48]  Wang Yao,et al.  Valley-contrasting physics in graphene: magnetic moment and topological transport. , 2007, Physical review letters.

[49]  Michelle Taylor,et al.  A highly stable N-heterocyclic carbene complex of trichloro-oxo-vanadium(V) displaying novel Cl-Ccarbene bonding interactions. , 2003, Journal of the American Chemical Society.

[50]  J. Coleman,et al.  Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials , 2011, Science.

[51]  Photonic Crystals for Enhanced Light Extraction from 2D Materials , 2016, 1607.04973.

[52]  Wang Yao,et al.  Valley-dependent optoelectronics from inversion symmetry breaking , 2007, 0705.4683.