scholarly journals Manipulating spin-polarized photocurrents in 2D transition metal dichalcogenides

2016 ◽  
Vol 113 (14) ◽  
pp. 3746-3750 ◽  
Author(s):  
Lu Xie ◽  
Xiaodong Cui
Keyword(s):  
Transition Metal ◽  
Spin Polarization ◽  
Electric Fields ◽  
Optical Pumping ◽  
Transition Metal Dichalcogenides ◽  
Spin Valve ◽  
Optical Fields ◽  
Spin Polarized ◽  
Valve Structure ◽  
Metal Dichalcogenides

Manipulating spin polarization of electrons in nonmagnetic semiconductors by means of electric fields or optical fields is an essential theme of the conceptual nonmagnetic semiconductor-based spintronics. Here we experimentally demonstrate an electric method of detecting spin polarization in monolayer transition metal dichalcogenides (TMDs) generated by circularly polarized optical pumping. The spin-polarized photocurrent is achieved through the valley-dependent optical selection rules and the spin–valley locking in monolayer WS2, and electrically detected by a lateral spin–valve structure with ferromagnetic contacts. The demonstrated long spin–valley lifetime, the unique valley-contrasted physics, and the spin–valley locking make monolayer WS2 an unprecedented candidate for semiconductor-based spintronics.

scholarly journals Tunable spin-valley coupling in layered polar Dirac metals

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Masaki Kondo ◽  
Masayuki Ochi ◽  
Tatsuhiro Kojima ◽  
Ryosuke Kurihara ◽  
Daiki Sekine ◽  
...  
Keyword(s):  
Transition Metal ◽  
Spin Polarization ◽  
Transition Metal Dichalcogenides ◽  
Spin Orbit Coupling ◽  
Dirac Fermions ◽  
Fermi Surfaces ◽  
Haas Oscillation ◽  
Spin Polarized ◽  
Metal Dichalcogenides ◽  
Inversion Asymmetry

AbstractIn non-centrosymmetric metals, spin-orbit coupling induces momentum-dependent spin polarization at the Fermi surfaces. This is exemplified by the valley-contrasting spin polarization in monolayer transition metal dichalcogenides with in-plane inversion asymmetry. However, the valley configuration of massive Dirac fermions in transition metal dichalcogenides is fixed by the graphene-like structure, which limits the variety of spin-valley coupling. Here, we show that the layered polar metal BaMnX2 (X = Bi, Sb) hosts tunable spin-valley-coupled Dirac fermions, which originate from the distorted X square net with in-plane lattice polarization. We found that BaMnBi2 has approximately one-tenth the lattice distortion of BaMnSb2, from which a different configuration of spin-polarized Dirac valleys is theoretically predicted. This was experimentally observed as a clear difference in the Shubnikov-de Haas oscillation at high fields between the two materials. The chemically tunable spin-valley coupling in BaMnX2 makes it a promising material for various spin-valleytronic devices.

scholarly journals Tunable Spin-Polarized Edge Currents in Proximitized Transition Metal Dichalcogenides

2019 ◽  
Vol 122 (8) ◽  
Author(s):  
Natalia Cortés ◽  
O. Ávalos-Ovando ◽  
L. Rosales ◽  
P. A. Orellana ◽  
S. E. Ulloa
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Spin Polarized ◽  
Metal Dichalcogenides

Strain-driven Phase Transition and Spin Polarization of Re-doped Transition-Metal Dichalcogenides

2021 ◽  
Author(s):  
Ruining Wang ◽  
Chen-Dong Jin ◽  
Hu Zhang ◽  
Ru-Qian Lian ◽  
Xingqiang Shi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Properties ◽  
Transition Metal ◽  
Spin Polarization ◽  
Transition Metal Dichalcogenides ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Energy Landscapes ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides (TMDCs) are promising in spintronics due to their spin-orbit coupling, but the intrinsic non-magnetic properties limit their further developments. Here, we focus on the energy landscapes...

scholarly journals Optically initialized robust valley-polarized holes in monolayer WSe2

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Wei-Ting Hsu ◽  
Yen-Lun Chen ◽  
Chang-Hsiao Chen ◽  
Pang-Shiuan Liu ◽  
Tuo-Hung Hou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Low Temperatures ◽  
Room Temperature ◽  
Optical Pumping ◽  
Transition Metal Dichalcogenides ◽  
Kerr Rotation ◽  
Time Resolved ◽  
Recombination Lifetime ◽  
Valley Polarization ◽  
Metal Dichalcogenides

Abstract A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin–valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (∼10–20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.

scholarly journals Optical properties of atomically thin transition metal dichalcogenides: observations and puzzles

Nanophotonics ◽  
2017 ◽  
Vol 6 (6) ◽  
pp. 1289-1308 ◽  
Author(s):  
Maciej Koperski ◽  
Maciej R. Molas ◽  
Ashish Arora ◽  
Karol Nogajewski ◽  
Artur O. Slobodeniuk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Optical Pumping ◽  
Single Photon ◽  
Hexagonal Boron Nitride ◽  
Transition Metal Dichalcogenides ◽  
Wide Band ◽  
Open Questions ◽  
Single Photon Emitters ◽  
Metal Dichalcogenides

AbstractRecent results on the optical properties of monolayer and few layers of semiconducting transition metal dichalcogenides are reviewed. Experimental observations are presented and discussed in the frame of existing models, highlighting the limits of our understanding in this emerging field of research. We first introduce the representative band structure of these systems and their interband optical transitions. The effect of an external magnetic field is then considered to discuss Zeeman spectroscopy and optical pumping experiments, both revealing phenomena related to the valley degree of freedom. Finally, we discuss the observation of single photon emitters in different types of layered materials, including wide band gap hexagonal boron nitride. While going through these topics, we try to focus on open questions and on experimental observations, which do not yet have a clear explanation.

scholarly journals Strong light-matter coupling in topological metasurfaces integrated with transition metal dichalcogenides

2021 ◽  
Vol 2015 (1) ◽  
pp. 012142
Author(s):  
Ivan Sinev ◽  
Mengyao Li ◽  
Fedor Benimetskiy ◽  
Tatiana Ivanova ◽  
Svetlana Kiriushechkina ◽  
...  
Keyword(s):  
Transition Metal ◽  
Topological Charge ◽  
Transition Metal Dichalcogenides ◽  
Strong Coupling Regime ◽  
Strong Light ◽  
Matter Coupling ◽  
Spin Polarized ◽  
Exciton Polaritons ◽  
Metal Dichalcogenides ◽  
Quantum Phenomena

Abstract Strong light-matter interactions enable unique nonlinear and quantum phenomena at moderate light intensities. Within the last years, polaritonic metasurfaces emerged as a viable candidate for realization of such regimes. In particular, planar photonic structures integrated with 2D excitonic materials, such as transition metal dichalcogenides (TMD), can support exciton polaritons – half-light half-matter quasiparticles. Here, we explore topological exciton polaritons which are formed in a suitably engineered all-dielectric topological photonic metasurface coupled to TMD monolayers. We experimentally demonstrate the transition of topological charge from photonic to polaritonic bands with the onset of strong coupling regime and confirm the presence of one-way spin-polarized edge topological polaritons. The proposed system constitutes a promising platform for photonic/solid-state interfaces for valleytronics and spintronics.

Band evolution of two-dimensional transition metal dichalcogenides under electric fields

2019 ◽  
Vol 115 (8) ◽  
pp. 083104
Author(s):  
Peng Chen ◽  
Cai Cheng ◽  
Cheng Shen ◽  
Jing Zhang ◽  
Shuang Wu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electric Fields ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
Metal Dichalcogenides
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