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Yu Y, Cheng M, Tao Z, Han W, Du G, Guo Y, Shi J, Chen Y. Phase-Modulated Elastic Properties of 2D Magnetic FeTe: Hexagonal and Tetragonal Polymorphs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2308357. [PMID: 38050942 DOI: 10.1002/smll.202308357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/01/2023] [Indexed: 12/07/2023]
Abstract
2D layered magnets, such as iron chalcogenides, have emerged these years as a new family of unconventional superconductors and provided the key insights to understand the phonon-electron interaction and pairing mechanism. Their mechanical properties are of strategic importance for the potential applications in spintronics and optoelectronics. However, there is still a lack of efficient approach to tune the elastic modulus despite the extensive studies. Herein, the modulated elastic modulus of 2D magnetic FeTe and its thickness-dependence is reported via phase engineering. The grown 2D FeTe by chemical vapor deposition can present various polymorphs, that is tetragonal FeTe (t-FeTe, antiferromagnetic) and hexagonal FeTe (h-FeTe, ferromagnetic). The measured Young's modulus of t-FeTe by nanoindentation method shows an obvious thickness-dependence, from 290.9 ± 9.2 to 113.0 ± 8.7 GPa when the thicknesses increased from 13.2 to 42.5 nm, respectively. In comparison, the elastic modulus of h-FeTe remains unchanged. These results can shed light on the efficient modulation of mechanical properties of 2D magnetic materials and pave the avenues for their practical applications in nanodevices.
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Affiliation(s)
- Yunfei Yu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Mo Cheng
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Zicheng Tao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 200031, P. R. China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 201210, P. R. China
| | - Wuxiao Han
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Guoshuai Du
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 200031, P. R. China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 201210, P. R. China
| | - Jianping Shi
- The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P. R. China
| | - Yabin Chen
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China
- Advanced Research Institute of Multidisciplinary Sciences, Beijing Institute of Technology, Beijing, 100081, P. R. China
- BIT Chongqing Institute of Microelectronics and Microsystems, Chongqing, 400030, P. R. China
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Hou Y, Zhou J, Xue M, Yu M, Han Y, Zhang Z, Lu Y. Strain Engineering of Twisted Bilayer Graphene: The Rise of Strain-Twistronics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311185. [PMID: 38616775 DOI: 10.1002/smll.202311185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 03/24/2024] [Indexed: 04/16/2024]
Abstract
The layer-by-layer stacked van der Waals structures (termed vdW hetero/homostructures) offer a new paradigm for materials design-their physical properties can be tuned by the vertical stacking sequence as well as by adding a mechanical twist, stretch, and hydrostatic pressure to the atomic structure. In particular, simple twisting and stacking of two layers of graphene can form a uniform and ordered Moiré superlattice, which can effectively modulate the electrons of graphene layers and lead to the discovery of unconventional superconductivity and strong correlations. However, the twist angle of twisted bilayer graphene (tBLG) is almost unchangeable once the interlayer stacking is determined, while applying mechanical elastic strain provides an alternative way to deeply regulate the electronic structure by controlling the lattice spacing and symmetry. In this review, diverse experimental advances are introduced in straining tBLG by in-plane and out-of-plane modes, followed by the characterizations and calculations toward quantitatively tuning the strain-engineered electronic structures. It is further discussed that the structural relaxation in strained Moiré superlattice and its influence on electronic structures. Finally, the conclusion entails prospects for opportunities of strained twisted 2D materials, discussions on existing challenges, and an outlook on the intriguing emerging field, namely "strain-twistronics".
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Affiliation(s)
- Yuan Hou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Jingzhuo Zhou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Minmin Xue
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Maolin Yu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Ying Han
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Zhuhua Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
| | - Yang Lu
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong, Hong Kong SAR, 999077, China
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Stellino E, D'Alò B, Blundo E, Postorino P, Polimeni A. Fine-Tuning of the Excitonic Response in Monolayer WS 2 Domes via Coupled Pressure and Strain Variation. NANO LETTERS 2024; 24:3945-3951. [PMID: 38506837 DOI: 10.1021/acs.nanolett.4c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
We present a spectroscopic investigation of the vibrational and optoelectronic properties of WS2 domes in the 0-0.65 GPa range. The pressure evolution of the system morphology, deduced by the combined analysis of Raman and photoluminescence spectra, revealed a significant variation in the dome's aspect ratio. The modification of the dome shape caused major changes in the mechanical properties of the system resulting in a sizable increase of the out-of-plane compressive strain while keeping the in-plane tensile strain unchanged. The variation of the strain gradients drives a nonlinear behavior in both the exciton energy and radiative recombination intensity, interpreted as the consequence of a hybridization mechanism between the electronic states of two distinct minima in the conduction band. Our results indicate that pressure and strain can be efficiently combined in low dimensional systems with unconventional morphology to obtain modulations of the electronic band structure not achievable in planar crystals.
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Affiliation(s)
- Elena Stellino
- Department of Basic and Applied Sciences for Engineering, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Beatrice D'Alò
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Elena Blundo
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Paolo Postorino
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Antonio Polimeni
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Roma, Italy
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Xu T, Wu C, Zheng S, Wang Y, Wang J, Hirakata H, Kitamura T, Shimada T. Mechanical Rippling for Diverse Ferroelectric Topologies in Otherwise Nonferroelectric SrTiO_{3} Nanofilms. PHYSICAL REVIEW LETTERS 2024; 132:086801. [PMID: 38457703 DOI: 10.1103/physrevlett.132.086801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/18/2023] [Accepted: 01/12/2024] [Indexed: 03/10/2024]
Abstract
Polar topological structures such as skyrmions and merons have become an emerging research field due to their rich functionalities and promising applications in information storage. Up to now, the obtained polar topological structures are restricted to a few limited ferroelectrics with complex heterostructures, limiting their large-scale practical applications. Here, we circumvent this limitation by utilizing a nanoscale ripple-generated flexoelectric field as a universal means to create rich polar topological configurations in nonpolar nanofilms in a controllable fashion. Our extensive phase-field simulations show that a rippled SrTiO_{3} nanofilm with a single bulge activates polarizations that are stabilized in meron configurations, which further undergo topological transitions to Néel-type and Bloch-type skyrmions upon varying the geometries. The formation of these topologies originates from the curvature-dependent flexoelectric field, which extends beyond the common mechanism of geometric confinement that requires harsh energy conditions and strict temperature ranges. We further demonstrate that the rippled nanofilm with three-dimensional ripple patterns can accommodate other unreported modulated phases of ferroelectric topologies, which provide ferroelectric analogs to the complex spin topologies in magnets. The present study not only unveils the intriguing nanoscale electromechanical properties but also opens exciting opportunities to design various functional topological phenomena in flexible materials.
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Affiliation(s)
- Tao Xu
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Chengsheng Wu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Sizheng Zheng
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China
| | - Yu Wang
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Jie Wang
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China
- Zhejiang Laboratory, Hangzhou 311100, Zhejiang, China
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takayuki Kitamura
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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El Hamdaoui J, Pérez LM, Ojeda-Martínez M, El Ouarie N, Díaz P, Laroze D, Feddi EM. First Principle Study on the Effect of Strain on the Electronic Structure and Carrier Mobility of the Janus MoSTe and WSTe Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2535. [PMID: 37764563 PMCID: PMC10534868 DOI: 10.3390/nano13182535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/25/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
Using first-principle calculations, we investigate the impact of strain on the electronic structures and effective masses of Janus WSTe and MoSTe monolayers. The calculations were performed using the QUANTUM-ESPRESSO package, employing the PBE and HSE06 functionals. Our results demonstrate that strain fundamentally changes the electronic structures of the Janus WSTe and MoSTe monolayers. We observe that deformation causes a shift in the maxima and minima of the valence and conduction bands, respectively. We find that the effective electrons and hole masses of MoSTe and WSTe can be changed by deformation. In addition, the strain's effect on carrier mobility is also investigated in this work via the deformation potential theory.
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Affiliation(s)
- Jawad El Hamdaoui
- Laboratory of Condensed Matter and Interdisciplinary Sciences (LaMCScI), Faculty of Sciences Rabat, Mohammed V University in Rabat, Rabat 10000, Morocco; (J.E.H.)
- Group of Optoelectronic of Semiconductors and Nanomaterials, ENSET of Rabat, Mohammed V University in Rabat, Rabat 10000, Morocco
| | - Laura M. Pérez
- Departamento de Física, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile;
| | - Miguel Ojeda-Martínez
- Centro Universitario de los Valles, Universidad de Guadalajara, Carretera Guadalajara-Ameca, Ameca 46600, Jalisco, Mexico
| | - Nassima El Ouarie
- Laboratory of Condensed Matter and Interdisciplinary Sciences (LaMCScI), Faculty of Sciences Rabat, Mohammed V University in Rabat, Rabat 10000, Morocco; (J.E.H.)
- Group of Optoelectronic of Semiconductors and Nanomaterials, ENSET of Rabat, Mohammed V University in Rabat, Rabat 10000, Morocco
| | - Pablo Díaz
- Departamento de Ciencias Físicas, Universidad de La Frontera, Casilla 54-D, Temuco 4780000, Chile
| | - David Laroze
- Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica 1000000, Chile
| | - El Mustapha Feddi
- Group of Optoelectronic of Semiconductors and Nanomaterials, ENSET of Rabat, Mohammed V University in Rabat, Rabat 10000, Morocco
- Institute of Applied Physics, Mohammed VI Polytechnic University, Lot 660, Hay Moulay Rachid, Ben Guerir 43150, Morocco
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Han Y, Gao L, Zhou J, Hou Y, Jia Y, Cao K, Duan K, Lu Y. Deep Elastic Strain Engineering of 2D Materials and Their Twisted Bilayers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:8655-8663. [PMID: 35147415 DOI: 10.1021/acsami.1c23431] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Conventionally, tuning materials' properties can be done through strategies such as alloying, doping, defect engineering, and phase engineering, while in fact mechanical straining can be another effective approach. In particular, elastic strain engineering (ESE), unlike conventional strain engineering mainly based on epitaxial growth, allows for continuous and reversible modulation of material properties by mechanical loading/unloading. The exceptional intrinsic mechanical properties (including elasticity and strength) of two-dimensional (2D) materials make them naturally attractive candidates for potential ESE applications. Here, we demonstrated that using the strain effect to modulate the physical and chemical properties toward novel functional device applications, which could be a general strategy for various 2D materials and their heterostructures. We then show how ultralarge, uniform elastic strain in free-standing 2D monolayers can permit deep elastic strain engineering (DESE), which can result in fundamentally changed electronic and optoelectronic properties for unconventional device applications. In addition to monolayers and van der Waals (vdW) heterostructures, we propose that DESE can be also applied to twisted bilayer graphene and other emerging twisted vdW structures, allowing for unprecedented functional 2D material applications.
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Affiliation(s)
- Ying Han
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Libo Gao
- School of Mechano-Electronic Engineering, Xidian University, Xi'an 710071, China
- CityU-Xidian Joint Laboratory of Micro/Nano-Manufacturing, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
| | - Jingzhuo Zhou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Yuan Hou
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Yanwen Jia
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ke Cao
- School of Mechano-Electronic Engineering, Xidian University, Xi'an 710071, China
- CityU-Xidian Joint Laboratory of Micro/Nano-Manufacturing, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
| | - Ke Duan
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
| | - Yang Lu
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
- CityU-Xidian Joint Laboratory of Micro/Nano-Manufacturing, Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong 999077, China
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Feng S, Xu Z. Strain Characterization in Two-Dimensional Crystals. MATERIALS 2021; 14:ma14164460. [PMID: 34442983 PMCID: PMC8397944 DOI: 10.3390/ma14164460] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022]
Abstract
Two-dimensional (2D) crystals provides a material platform to explore the physics and chemistry at the single-atom scale, where surface characterization techniques can be applied straightforwardly. Recently there have been emerging interests in engineering materials through structural deformation or transformation. The strain field offers crucial information of lattice distortion and phase transformation in the native state or under external perturbation. Example problems with significance in science and engineering include the role of defects and dislocations in modulating material behaviors, and the process of fracture, where remarkable strain is built up in a local region, leading to the breakdown of materials. Strain is well defined in the continuum limit to measure the deformation, which can be alternatively calculated from the arrangement of atoms in discrete lattices through methods such as geometrical phase analysis from transmission electron imaging, bond distortion or virial stress from atomic structures obtained from molecular simulations. In this paper, we assess the accuracy of these methods in quantifying the strain field in 2D crystals through a number of examples, with a focus on their localized features at material imperfections. The sources of errors are discussed, providing a reference for reliable strain mapping.
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