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Related papers: Anomalous valley polarization in monolayer MoSe2

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The circular polarization (CP) that the photoluminescence inherits from the excitation source in n monolayers of transition-metal dichalcogenides (MX2)n has been previously explained as a special feature of odd values of n, where the…

Materials Science · Physics 2015-03-02 Qihang Liu , Xiuwen Zhang , Alex Zunger

In monolayer transition metal dichalcogenide semiconductors, valley coherence degrades rapidly due to a combination of fast scattering and inter-valley exchange interaction. This leads to a sub-picosecond valley coherence time, making…

Mesoscale and Nanoscale Physics · Physics 2023-07-21 Garima Gupta , Kenji Watanabe , Takashi Taniguchi , Kausik Majumdar

Transition metal dichalcogenide semiconductors represent elementary components of layered heterostructures for emergent technologies beyond conventional opto-electronics. In their monolayer form they host electrons with quantized circular…

The rise of quantum science and technologies motivates photonics research to seek new platforms with strong light-matter interactions to facilitate quantum behaviors at moderate light intensities. One promising platform to reach such strong…

Monolayer transition metal dichalcogenides have attracted great attentions for potential applications in valleytronics. However, the valley polarization degree is usually not high because of the intervalley scattering. Here, we demonstrate…

Materials Science · Physics 2023-02-23 Jianchen Dang , Mingwei Yang , Xin Xie , Zhen Yang , Danjie Dai , Zhanchun Zuo , Can Wang , Kuijuan Jin , Xiulai Xu

Spin- and angle-resolved photoemission spectroscopy is used to reveal that a large spin polarization is observable in the bulk centrosymmetric transition metal dichalcogenide MoS2. It is found that the measured spin polarization can be…

In atomically thin transition metal dichalcogenides (TMDs), reduced dielectric screening of the Coulomb interaction leads to strongly correlated many-body states, including excitons and trions, that dominate the optical properties.…

Due to degeneracies arising from crystal symmetries, it is possible for electron states at band edges ("valleys") to have additional spin-like quantum numbers. An important question is whether coherent manipulation can be performed on such…

Monolayers of transition metal dichalcogenides are ideal materials to control both spin and valley degrees of freedom either electrically or optically. Nevertheless, optical excitation mostly generates excitons species with inherently short…

Achieving robust and electrically controlled valley polarization in monolayer transition metal dichalcogenides (ML-TMDs) is a frontier challenge for realistic valleytronic applications. Theoretical investigations show that integration of 2D…

Valley polarization (VP), an induced imbalance in the populations of a multi-valley electronic system, allows emission of second harmonic (SH) light even in centrosymmetric crystals such as graphene. Whereas in systems such as…

Mesoscale and Nanoscale Physics · Physics 2017-06-16 F. Hipolito , Vitor M. Pereira

Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly-bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong…

We investigate the valley coherence in high and low-quality monolayer MoSe2 by polarization-resolved photoluminescence spectroscopy. The observed valley coherence is on the order of 10 % regardless of the sample quality, proving that the…

Materials Science · Physics 2023-06-28 Yuto Urano , Xue Mengsong , Kenji Watanabe , Takashi Taniguchi , Ryo Kitaura

Transition-metal dichalcogenides can be easily produced as atomically thin sheets, exhibiting the possibility to optically polarize and read out the valley pseudospin of extremely stable excitonic quasiparticles present in these 2D…

The band structure of transition metal dichalcogenides (TMDCs) with valence band edges at different locations in the momentum space could be harnessed to build devices that operate relying on the valley degree of freedom. To realize such…

Mesoscale and Nanoscale Physics · Physics 2016-09-06 Oriol Lopez Sanchez , Dmitry Ovchinnikov , Shikhar Misra , Adrien Allain , Andras Kis

Light emission from higher-order correlated excitonic states has been recently reported in hBN-encapsulated monolayer WSe2 and WS2 upon optical excitation. These exciton complexes are found to be bound states of excitons residing in…

Mesoscale and Nanoscale Physics · Physics 2019-04-19 Matthias Paur , Aday J. Molina-Mendoza , Rudolf Bratschitsch , Kenji Watanabe , Takashi Taniguchi , Thomas Mueller

Reliable optical control of valley degrees of freedom in moir\'e excitons requires that the emitted polarization faithfully reflect the underlying valley state. Here, we show that linearly polarized photoluminescence from WSe2/WS2 moir\'e…

We show that inversion symmetry breaking together with spin-orbit coupling leads to coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides, making possible controls of spin and valley in these 2D materials.…

Mesoscale and Nanoscale Physics · Physics 2012-05-09 Di Xiao , Gui-Bin Liu , Wanxiang Feng , Xiaodong Xu , Wang Yao

A new degree of freedom, the valley pseudospin, emerges in atomically thin two-dimensional transition metal dichalcogenides (MX2) and has attracted great scientific interest. The capability to manipulate the valley pseudospin, in analogy to…

Mesoscale and Nanoscale Physics · Physics 2014-12-10 Jonghwan Kim , Xiaoping Hong , Chenhao Jin , Su-Fei Shi , Chih-Yuan S. Chang , Ming-Hui Chiu , Lain-Jong Li , Feng Wang

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…

Mesoscale and Nanoscale Physics · Physics 2016-03-31 Xie Lu , Xiaodong Cui