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Your search keyword '"Qiu, Cheng-Wei"' showing total 191 results
Start Over Author "Qiu, Cheng-Wei" Journal nature communications
191 results on '"Qiu, Cheng-Wei"'

22. Tunable analog thermal material.

Author

Xu, Guoqiang, Dong, Kaichen, Li, Ying, Li, Huagen, Liu, Kaipeng, Li, Longqiu, Wu, Junqiao, and Qiu, Cheng-Wei

Abstract

Naturally-occurring thermal materials usually possess specific thermal conductivity (κ), forming a digital set of κ values. Emerging thermal metamaterials have been deployed to realize effective thermal conductivities unattainable in natural materials. However, the effective thermal conductivities of such mixing-based thermal metamaterials are still in digital fashion, i.e., the effective conductivity remains discrete and static. Here, we report an analog thermal material whose effective conductivity can be in-situ tuned from near-zero to near-infinity κ. The proof-of-concept scheme consists of a spinning core made of uncured polydimethylsiloxane (PDMS) and fixed bilayer rings made of silicone grease and steel. Thanks to the spinning PDMS and its induced convective effects, we can mold the heat flow robustly with continuously changing and anisotropic κ. Our work enables a single functional thermal material to meet the challenging demands of flexible thermal manipulation. It also provides platforms to investigate heat transfer in systems with moving components.

Published
2020

39. Dielectric multi-momentum meta-transformer in the visible

Author

Jin, Lei, Huang, Yao-Wei, Jin, Zhongwei, Devlin, Robert C., Dong, Zhaogang, Mei, Shengtao, Jiang, Menghua, Chen, Wei Ting, Wei, Zhun, Liu, Hong, Teng, Jinghua, Danner, Aaron, Li, Xiangping, Xiao, Shumin, Zhang, Shuang, Yu, Changyuan, Yang, Joel K. W., Capasso, Federico, and Qiu, Cheng-Wei

Published
2019
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44. Observation of bulk quadrupole in topological heat transport.

Author

Xu, Guoqiang, Zhou, Xue, Yang, Shuihua, Wu, Jing, and Qiu, Cheng-Wei

Subjects
QUADRUPOLE moments, QUADRUPOLES, THERMAL engineering, METAMATERIALS, NUCLEAR quadrupole resonance, QUANTUM spin Hall effect, PHYSICS
Abstract

The quantized bulk quadrupole moment has so far revealed a non-trivial boundary state with lower-dimensional topological edge states and in-gap zero-dimensional corner modes. In contrast to photonic implementations, state-of-the-art strategies for topological thermal metamaterials struggle to achieve such higher-order hierarchical features. This is due to the absence of quantized bulk quadrupole moments in thermal diffusion fundamentally prohibiting possible band topology expansions. Here, we report a recipe for generating quantized bulk quadrupole moments in fluid heat transport and observe the quadrupole topological phases in non-Hermitian thermal systems. Our experiments show that both the real- and imaginary-valued bands exhibit the hierarchical features of bulk, gapped edge and in-gap corner states—in stark contrast to the higher-order states observed only on real-valued bands in classical wave fields. Our findings open up unique possibilities for diffusive metamaterial engineering and establish a playground for multipolar topological physics. Topological transport in thermal diffusion is governed by physical principles that are distinct from those encountered in solid-state or photonic topological systems. Here, the authors demonstrate an experimental strategy for engineering topological thermal phases with bulk, edge and corner modes. [ABSTRACT FROM AUTHOR]

Published
2023
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45. Growth of bilayer MoTe2 single crystals with strong non-linear Hall effect.

Author

Ma, Teng, Chen, Hao, Yananose, Kunihiro, Zhou, Xin, Wang, Lin, Li, Runlai, Zhu, Ziyu, Wu, Zhenyue, Xu, Qing-Hua, Yu, Jaejun, Qiu, Cheng Wei, Stroppa, Alessandro, and Loh, Kian Ping

Subjects
SINGLE crystals, SPIN-orbit interactions, TRANSITION metals, HALL effect, TOPOLOGICAL property, BILAYERS (Solid state physics), FERROELECTRICITY, CHEMICAL vapor deposition
Abstract

The reduced symmetry in strong spin-orbit coupling materials such as transition metal ditellurides (TMDTs) gives rise to non-trivial topology, unique spin texture, and large charge-to-spin conversion efficiencies. Bilayer TMDTs are non-centrosymmetric and have unique topological properties compared to monolayer or trilayer, but a controllable way to prepare bilayer MoTe2 crystal has not been achieved to date. Herein, we achieve the layer-by-layer growth of large-area bilayer and trilayer 1T′ MoTe2 single crystals and centimetre-scale films by a two-stage chemical vapor deposition process. The as-grown bilayer MoTe2 shows out-of-plane ferroelectric polarization, whereas the monolayer and trilayer crystals are non-polar. In addition, we observed large in-plane nonlinear Hall (NLH) effect for the bilayer and trilayer Td phase MoTe2 under time reversal-symmetric conditions, while these vanish for thicker layers. For a fixed input current, bilayer Td MoTe2 produces the largest second harmonic output voltage among the thicker crystals tested. Our work therefore highlights the importance of thickness-dependent Berry curvature effects in TMDTs that are underscored by the ability to grow thickness-precise layers. 2D transition metal ditellurides exhibit nontrivial topological phases, but the controlled bottom-up synthesis of these materials is still challenging. Here, the authors report the layer-by-layer growth of large-area bilayer and trilayer 1T' MoTe2 films, showing thickness-dependent ferroelectricity and nonlinear Hall effect. [ABSTRACT FROM AUTHOR]

Published
2022
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46. Structural color three-dimensional printing by shrinking photonic crystals

Author

Liu, Yejing, primary, Wang, Hao, additional, Ho, Jinfa, additional, Ng, Ryan C., additional, Ng, Ray J. H., additional, Hall-Chen, Valerian H., additional, Koay, Eleen H. H., additional, Dong, Zhaogang, additional, Liu, Hailong, additional, Qiu, Cheng-Wei, additional, Greer, Julia R., additional, and Yang, Joel K. W., additional

Published
2019
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49. Slow cooling and efficient extraction of C-exciton hot carriers in MoS2 monolayer

Author

Wang, Lei, primary, Wang, Zhuo, additional, Wang, Hai-Yu, additional, Grinblat, Gustavo, additional, Huang, Yu-Li, additional, Wang, Dan, additional, Ye, Xiao-Hui, additional, Li, Xian-Bin, additional, Bao, Qiaoliang, additional, Wee, AndrewThye-Shen, additional, Maier, Stefan A, additional, Chen, Qi-Dai, additional, Zhong, Min-Lin, additional, Qiu, Cheng-Wei, additional, and Sun, Hong-Bo, additional

Published
2017
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