PHYSICAL CHEMISTRY CHEMICAL PHYSICS
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2023
·Vol. 25
·期 28
·18998-19003
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IF 3.3
Guangcun Gao,Jintong Zhu,Songrui Wei,Yang Cao,Wei Huang,Zhongxin Liu,Jieqiong Wang,Yijun Shen
Monolayers of transition metal dichalcogenides (TMDCs) are atomically thin direct-bandgap semiconductors with potential applications in nanoelectronics, opto-electronics, and electrochemical sensing. Recent theoretical and experimental results have suggested that they are ideal systems for exploiting the valley degrees of freedom of Bloch electrons. Here, we report detailed studies of the opto-valleytronic properties of a chiral histidine molecule embedded in monolayer MoS2 single crystals grown via chemical vapor deposition. By irradiating MoS2 with circularly polarized light and measuring the resulting spatially resolved circularly polarized emission, we find the existence of a significantly increased circular polarization for D-histidine doped MoS2. The increased valley contrast is attributed to the selective enhancement of both the excitation and emission rates having one particular handedness of the circular polarization. These results provide a promising pathway to enhance the valley contrast for monolayer TMDCs at room temperature.
研究领域:
材料科学
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纳米技术
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光电学
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半导体物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nature Nanotechnology
·
2022
·Vol. 17
·期 11
·1178-1182
·
IF 40.523
Chen Yang,Qian Shuhang,Wang Kai,Xing Xiangyuan,Wee Andrew,Loh Kian Ping,Wang Bing,Wu Dong,Chu Jiaru,Alu Andrea,Lu Peixiang,Qiu Cheng-Wei
Valleytronics is a promising candidate to address low-energy signal transport on chip, leveraging the valley pseudospin of electrons as a new degree of freedom to encode, process and store information 1 , 2 , 3 , 4 , 5 , 6 , 7 . However, valley-carrier nanocircuitry is still elusive, because it essentially requires valley transport that overcomes three simultaneous challenges: high fidelity, high directionality and room-temperature operation. Here we experimentally demonstrate a nanophotonic circuit that can route valley indices of a WS 2 monolayer unidirectionally via the chirality of photons. Two propagating modes are supported in the gap area of the circuit and interfere with each other to generate beating patterns, which exhibit complementary profiles for circular dipoles of different handedness. Based on the spin-dependent beating patterns, we showcase valley fidelity of chiral photons up to 98%, and the circulation directionality is measured to be 0.44 ± 0.04 at room temperature. The proposed nanocircuit can not only enable the construction of large-scale valleytronic networks but also serve as an interactive interface to integrate valleytronics 3 , 4 , 5 , spintronics 8 , 9 , 10 and integrated photonics 11 , 12 , 13 , opening new possibilities for hybrid spin-valley-photon ecosystems at the nanoscale.
研究领域:
光子学
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纳米技术
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材料科学
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量子信息科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Gaohong Liu,Xuanli Zheng,Haiyang Liu,Jun Yin,Congming Ke,Weihuang Yang,Yaping Wu,Zhiming Wu,Xu Li,Chunmiao Zhang,Junyong Kang
Transition-metal dichalcogenides with intrinsic spin-valley degree of freedom have enabled great potentials for valleytronic and optoelectronic applications. However, the degree of valley polarization is usually low under nonresonant excitation at room temperature due to the phonon-assisted intervalley scattering. Here, achiral and chiral Au arrays are designed to enhance the optical response and valley polarization in monolayer and bilayer WS2. A considerable band edge emission with 7 times increment is realized under the resonant coupling with Au dimer-prism arrays. Valley polarization enhancement is quantitatively predicted by the inherent mechanisms from elevated electromagnetic field intensity and radiation efficiency and further realized in polarized photoluminescence. A tunable valley polarization up to 30.0% is achieved in bilayer WS2 under a nonresonant excitation at room temperature. All of these results provide a promising route toward the development of room-temperature valley-dependent optoelectronic devices.
研究领域:
光电子学
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谷电子学
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纳米光子学
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等离激元学
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凝聚态物理
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二维材料
✓ 已验证
DOI
高影响因子
ACS Nano
·
2021
·
IF 15.881
Haiyang Liu,Deyi Fu,Xu Li,Junbo Han,Xiaodie Chen,Xuefeng Wu,Baofan Sun,Weiqing Tang,Congming Ke,Yaping Wu,Zhiming Wu,Junyong Kang
Lifting the valley degeneracy in two-dimensional transition metal dichalcogenides could promote their applications in information processing. Various external regulations, including magnetic substrate, magnetic doping, electric field, and carrier doping, have been implemented to enhance the valley splitting under the magnetic field. Here, a phase engineering strategy, through modifying the intrinsic lattice structure, is proposed to enhance the valley splitting in monolayer WSe2. The valley splitting in hybrid H and T phase WSe2 is tunable by the concentration of the T phase. An obvious valley splitting of ∼4.1 meV is obtained with the T phase concentration of 31% under ±5 T magnetic fields, which corresponds to an effective Landé geff factor of −14, about 3.5-fold of that in pure H-WSe2. Comparing the temperature and magnetic field dependent polarized photoluminescence and also combining the theoretical simulations reveal the enhanced valley splitting is dominantly attributed to exchange interaction of H phase WSe2 with the local magnetic moments induced by the T phase. This finding provides a convenient solution for lifting the valley degeneracy of two-dimensional materials.
研究领域:
凝聚态物理
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材料科学
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谷电子学
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二维材料
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纳米技术
✓ 已验证
DOI
高影响因子
Advanced Electronic Materials
·
2022
·Vol. 9
·期 2
·2200852
·
IF 7.633
Yao Wang,Chaocheng Liu,Hengli Duan,Zhi Li,Chao Wang,Sihua Feng,Ruiqi Liu,Fengchun Hu,Hongfeng Jia,Huabin Yu,Lin Zhu,Yuran Niu,Alexei A. Zakharov,Haiding Sun,Wensheng Yan
The weak dielectric screening in 2D semiconducting transition metal dichalcogenides give rise to strongly bound quasiparticles, which provides a platform to investigate the diverse excitonic phenomena and correlated physics. However, how to effectively control these quasiparticles is still a challenge for their applications in optoelectronic and valleytronic devices. Herein, by means of fabricating monolayer WSe 2 and transition metal oxide (TMO) heterostructures, polaronic trion, that is a trion dressed with soft rotational optical (RO) phonons, is realized due to the strong interfacial coupling. This Fröhlich bound state of trion dramatically increases the trion binding energy (BE) from room temperature to 65 meV at 80 K in WSe 2 /LaAlO 3 (LAO). However, the increase of the trion BE for WSe 2 /SrTiO 3 (STO) occurs below the phase transition temperature. This work expands the possibilities of the TMDs/TMOs heterostructures and promotes the development of 2D van der Waals materials for quasiparticle-based devices.
研究领域:
凝聚态物理
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二维材料
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光电子学
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谷电子学
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量子材料
✓ 已验证
DOI
高影响因子
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