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Qin Z, Dai L, Li M, Li S, Wu H, White KE, Gani G, Weiss PS, Hu Y. Moiré Pattern Controlled Phonon Polarizer Based on Twisted Graphene. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312176. [PMID: 38429904 PMCID: PMC11180428 DOI: 10.1002/adma.202312176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/23/2024] [Indexed: 03/03/2024]
Abstract
Twisted van der Waals materials featuring Moiré patterns present new design possibilities and demonstrate unconventional behaviors in electrical, optical, spintronic, and superconducting properties. However, experimental exploration of thermal transport across Moiré patterns has not been as extensive, despite its critical role in nanoelectronics, thermal management, and energy technologies. Here, the first experimental study is conducted on thermal transport across twisted graphene, demonstrating a phonon polarizer concept from the rotational misalignment between stacked layers. The direct thermal and acoustic measurements, structural characterizations, and atomistic modeling, reveal a modulation up to 631% in thermal conductance with various Moiré angles, while maintaining a high acoustic transmission. By comparing experiments with density functional theory and molecular dynamics simulations, mode-dependent phonon transmissions are quantified based on the angle alignment of graphene band structures and attributed to the coupling among flexural phonon modes. The agreement confirms the dominant tuning mechanisms in adjusting phonon transmission from high-frequency thermal modes while having negligible effects on low-frequency acoustic modes near Brillouin zone center. This study offers crucial insights into the fundamental thermal transport in Moiré structures, opening avenues for the invention of quantum thermal devices and new design methodologies based on manipulations of vibrational band structures and phonon spectra.
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Affiliation(s)
- Zihao Qin
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lingyun Dai
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Man Li
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Suixuan Li
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Huan Wu
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Katherine E. White
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Gilad Gani
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Paul S. Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Yongjie Hu
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
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Sun Q, Liu W, Huang D, Huang X, Xu S, Wang J, Ye Z, Wang X, Wu S, Yue Y. Molecular dynamics study on thermal conductance between a nanotip and a substrate under vertical forces and horizontal sliding. Phys Chem Chem Phys 2023; 25:5510-5519. [PMID: 36723186 DOI: 10.1039/d2cp04655e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The heat transfer between a nanotip and its substrate is extremely complex but is a key factor in determining the measurement accuracy in tip-assisted nanomanufacturing and thermometry. In this work, the heat transfer from the nanotip to the substrate during sliding is investigated using molecular dynamics simulations. Interfacial interaction and bond formation are analyzed during the sliding process. The results show that the increase of vertical force would greatly improve the interface thermal conductance between the nanotip and the substrate. It is found that more bonds are formed and there are larger contact areas at the interface. In addition, we found that the thermal conductivity of the nanotip is another obstacle for heat transfer between the tip and substrate and it is greatly limited by the nanotip diameter near contact which is close to or even smaller than the phonon mean free path. Meanwhile, the dynamic formation and breakage of the covalent bonds during the sliding could gradually smoothen the tip apex and enhance the thermal transport at the interface. This work provides guidance for the thermal design of a nanotip-substrate system for nanoscale thermal transport measurements.
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Affiliation(s)
- Qiangsheng Sun
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Wenxiang Liu
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Dezhao Huang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Xiaona Huang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Shen Xu
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Jianmei Wang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Zhijiang Ye
- Department of Mechanical and Manufacturing Engineering, Miami University, Ohio 45056, USA
| | - Xiaosun Wang
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Shijing Wu
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
| | - Yanan Yue
- School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China. .,Department of Mechanical and Manufacturing Engineering, Miami University, Ohio 45056, USA
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Liu W, Hong Y, Zhang J, Yue Y. Anisotropic Thermal Transport in Twisted Bilayer Graphene. Phys Chem Chem Phys 2022; 24:21722-21728. [DOI: 10.1039/d2cp01896a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, twisted bilayer graphene (TBLG) has attracted significant attentions due to its peculiar electronic properties. In this work, we investigate the anisotropic thermal conductivity of TBLG and report that twisting...
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