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Bhattacharya S, Datta S. Rashba splitting in polar-nonpolar sandwich heterostructure: a DFT study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:405701. [PMID: 38979851 DOI: 10.1088/1361-648x/ad5d42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 06/28/2024] [Indexed: 07/10/2024]
Abstract
In this study, we employ density functional theory based first-principles calculations to investigate the spin-orbit effects in the electronic structure of a polar-nonpolar sandwich heterostructure namelyLaAlO3/SrTiO3/LaAlO3. Our focus on theTi-3dbands reveals an inverted ordering of theSrTiO3-t2gorbital near the n-type interface, which is consistent with earlier experimental work. In contrast, toward the p-type interface, the orbital ordering aligns with the natural ordering ofSrTiO3orbitals, influenced by crystal field splitting. In the presence of SOC, a notable inter-orbital coupling betweent2gandegorbitals is observed within the tetragonal slab, a phenomenon not reported before in theSrTiO3-based 2D systems. Additionally, our observations highlight that the cubic Rashba splitting in this system surpasses the linear Rashba splitting, contrary to experimental findings. This comprehensive analysis contributes to a refined understanding of the role of orbital mixing in Rashba splitting in the sandwich oxide heterostructures.
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Affiliation(s)
- Sanchari Bhattacharya
- Department of Physics and Astronomy, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Sanjoy Datta
- Department of Physics and Astronomy, National Institute of Technology, Rourkela 769008, Odisha, India
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2
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Xu H, Li H, Gauquelin N, Chen X, Wu WF, Zhao Y, Si L, Tian D, Li L, Gan Y, Qi S, Li M, Hu F, Sun J, Jannis D, Yu P, Chen G, Zhong Z, Radovic M, Verbeeck J, Chen Y, Shen B. Giant Tunability of Rashba Splitting at Cation-Exchanged Polar Oxide Interfaces by Selective Orbital Hybridization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313297. [PMID: 38475975 DOI: 10.1002/adma.202313297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/07/2024] [Indexed: 03/14/2024]
Abstract
The 2D electron gas (2DEG) at oxide interfaces exhibits extraordinary properties, such as 2D superconductivity and ferromagnetism, coupled to strongly correlated electrons in narrow d-bands. In particular, 2DEGs in KTaO3 (KTO) with 5d t2g orbitals exhibit larger atomic spin-orbit coupling and crystal-facet-dependent superconductivity absent for 3d 2DEGs in SrTiO3 (STO). Herein, by tracing the interfacial chemistry, weak anti-localization magneto-transport behavior, and electronic structures of (001), (110), and (111) KTO 2DEGs, unambiguously cation exchange across KTO interfaces is discovered. Therefore, the origin of the 2DEGs at KTO-based interfaces is dramatically different from the electronic reconstruction observed at STO interfaces. More importantly, as the interface polarization grows with the higher order planes in the KTO case, the Rashba spin splitting becomes maximal for the superconducting (111) interfaces approximately twice that of the (001) interface. The larger Rashba spin splitting couples strongly to the asymmetric chiral texture of the orbital angular moment, and results mainly from the enhanced inter-orbital hopping of the t2g bands and more localized wave functions. This finding has profound implications for the search for topological superconductors, as well as the realization of efficient spin-charge interconversion for low-power spin-orbitronics based on (110) and (111) KTO interfaces.
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Affiliation(s)
- Hao Xu
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hang Li
- Photon Science Division, Paul Scherrer Institute, Villigen, 5232, Switzerland
| | - Nicolas Gauquelin
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 4Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Xuejiao Chen
- CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Wen-Feng Wu
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, P. R. China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, 230026, P. R. China
| | - Yuchen Zhao
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Liang Si
- School of Physics, Northwest University, Xi'an, 710127, China
| | - Di Tian
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Lei Li
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials and Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
| | - Yulin Gan
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shaojin Qi
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minghang Li
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fengxia Hu
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jirong Sun
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Daen Jannis
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 4Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Pu Yu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Gang Chen
- Department of Physics and HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong, The University of Hong Kong, Hong Kong, 999077, China
| | - Zhicheng Zhong
- CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Milan Radovic
- Photon Science Division, Paul Scherrer Institute, Villigen, 5232, Switzerland
| | - Johan Verbeeck
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 4Groenenborgerlaan 171, Antwerp, 2020, Belgium
| | - Yunzhong Chen
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Baogen Shen
- Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS Key Laboratory of Magnetic Materials and Devices and Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
- Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou, Jiangxi, 341000, China
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Zhang B, Tang C, Yang P, Chen J. Tuning Rashba-Dresselhaus effect with ferroelectric polarization at asymmetric heterostructural interface. MATERIALS HORIZONS 2024; 11:262-270. [PMID: 37934455 DOI: 10.1039/d3mh00635b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The spin-orbit interaction (SOI) plays an essential role in materials properties, and controlling its intensity has great potential in the design of materials. In this work, asymmetric [(La0.7Sr0.3MnO3)8/(BaTiO3)t/(SrTiO3)2]8 superlattices were fabricated on (001) SrTiO3 substrate with SrO or TiO2 termination, labelled as SrO-SL and TiO2-SL, respectively. The in-plane angular magnetoresistance of the superlattices shows a combination of two- and four-fold symmetry components. The coefficient of two-fold symmetry component has opposite sign with current I along [100] and [110] directions for TiO2-SL, while it has the same sign for SrO-SL. Detailed study shows that the asymmetric cation inter-mixing and ferroelectricity-modulated electronic charge transfer induce asymmetric electronic potential for SrO-SL with dominating Rashba SOI, and symmetric electronic potential for TiO2-SL with dominating Dresselhaus SOI induced by BaTiO3. This work shows that the Rashba and Dresselhaus SOIs are sensitive to the ferroelectric polarization in the asymmetric structure.
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Affiliation(s)
- Bangmin Zhang
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
| | - Chunhua Tang
- Department of Materials Science & Engineering, National University of, Singapore, 9 Engineering Drive 1, 117576, Singapore.
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore
| | - Jingsheng Chen
- Department of Materials Science & Engineering, National University of, Singapore, 9 Engineering Drive 1, 117576, Singapore.
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Huang J, Dai S, Xu C, Du Y, Xu Z, Han K, Xu L, Wu W, Chen P, Huang Z. Capping-layer-mediated lattice mismatch and redox reaction in SrTiO 3-based bilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35. [PMID: 37059113 DOI: 10.1088/1361-648x/accd37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/14/2023] [Indexed: 05/16/2023]
Abstract
It is well known that the traditional two-dimensional electron system (2DES) hosted by the SrTiO3substrate can exhibit diverse electronic states by modifying the capping layer in heterostructures. However, such capping layer engineering is less studied in the SrTiO3-layer-carried 2DES (or bilayer 2DES), which is different from the traditional one on transport properties but more applicable to the thin-film devices. Here, several SrTiO3bilayers are fabricated by growing various crystalline and amorphous oxide capping layers on the epitaxial SrTiO3layers. For the crystalline bilayer 2DES, the monotonical reduction on the interfacial conductance, as well as carrier mobility, is recorded on increasing the lattice mismatch between the capping layers and epitaxial SrTiO3layer. The mobility edge raised by the interfacial disorders is highlighted in the crystalline bilayer 2DES. On the other hand, when increasing the concentration of Al with high oxygen affinity in the capping layer, the amorphous bilayer 2DES becomes more conductive accompanied by the enhanced carrier mobility but almost constant carrier density. This observation cannot be explained by the simple redox-reaction model, and the interfacial charge screening and band bending need to be considered. Moreover, when the capping oxide layers have the same chemical composition but with different forms, the crystalline 2DES with a large lattice mismatch is more insulating than its amorphous counterpart, and vice versa. Our results shed some light on understanding the different dominant role in forming the bilayer 2DES using crystalline and amorphous oxide capping layer, which may be applicable in designing other functional oxide interfaces.
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Affiliation(s)
- Jingwen Huang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Song Dai
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Chengcheng Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Yongyi Du
- Stony Brook Institute at Anhui University, Anhui University, Hefei 230039, People's Republic of China
| | - Zhipeng Xu
- Stony Brook Institute at Anhui University, Anhui University, Hefei 230039, People's Republic of China
| | - Kun Han
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Liqiang Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Wenbin Wu
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Pingfan Chen
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Zhen Huang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
- Stony Brook Institute at Anhui University, Anhui University, Hefei 230039, People's Republic of China
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Tunable Spin and Orbital Edelstein Effect at (111) LaAlO3/SrTiO3 Interface. NANOMATERIALS 2022; 12:nano12142494. [PMID: 35889717 PMCID: PMC9318607 DOI: 10.3390/nano12142494] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 12/04/2022]
Abstract
Converting charge current into spin current is one of the main mechanisms exploited in spintronics. One prominent example is the Edelstein effect, namely, the generation of a magnetization in response to an external electric field, which can be realized in systems with lack of inversion symmetry. If a system has electrons with an orbital angular momentum character, an orbital magnetization can be generated by the applied electric field, giving rise to the so-called orbital Edelstein effect. Oxide heterostructures are the ideal platform for these effects due to the strong spin–orbit coupling and the lack of inversion symmetries. Beyond a gate-tunable spin Edelstein effect, we predict an orbital Edelstein effect an order of magnitude larger then the spin one at the (111) LaAlO3/SrTiO3 interface for very low and high fillings. We model the material as a bilayer of t2g orbitals using a tight-binding approach, whereas transport properties are obtained in the Boltzmann approach. We give an effective model at low filling, which explains the non-trivial behaviour of the Edelstein response, showing that the hybridization between the electronic bands crucially impacts the Edelstein susceptibility.
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Chen M, Liu F. Prediction of giant and ideal Rashba-type splitting in ordered alloy monolayers grown on a polar surface. Natl Sci Rev 2021; 8:nwaa241. [PMID: 34691614 PMCID: PMC8288359 DOI: 10.1093/nsr/nwaa241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/14/2022] Open
Abstract
A large and ideal Rashba-type spin-orbit splitting is desired for the applications of materials in spintronic devices and the detection of Majorana fermions in solids. Here, we propose an approach to achieve giant and ideal spin-orbit splittings through a combination of ordered surface alloying and interface engineering, that is, growing alloy monolayers on an insulating polar surface. We illustrate this unique strategy by means of first-principle calculations of buckled hexagonal monolayers of SbBi and PbBi supported on Al2O3(0001). Both systems display ideal Rashba-type states with giant spin-orbit splittings, characterized with energy offsets over 600 meV and momentum offsets over 0.3 Å−1, respectively. Our study thus points to an effective way of tuning spin-orbit splitting in low-dimensional materials to draw immediate experimental interest.
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Affiliation(s)
- Mingxing Chen
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education, Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), School of Physics and Electronics, Hunan Normal University, Changsha 410081, China
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112, USA
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Zhou X, Liu Z. Nature of electrons from oxygen vacancies and polar catastrophe at LaAlO 3/SrTiO 3interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:435601. [PMID: 34320477 DOI: 10.1088/1361-648x/ac1883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
The relative significance of quantum conductivity correction and magnetic nature of electrons in understanding the intriguing low-temperature resistivity minimum and negative magnetoresistance (MR) of the two-dimensional electron gas at LaAlO3/SrTiO3interfaces has been a long outstanding issue since its discovery. Here we report a comparative magnetotransport study on amorphous and oxygen-annealed crystalline LaAlO3/SrTiO3heterostructures at a relatively high-temperature range, where the orbital scattering is largely suppressed by thermal fluctuations. Despite of a predominantly negative out-of-plane MR effect for both, the magnetotransport is isotropic for amorphous LaAlO3/SrTiO3while strongly anisotropic and well falls into a two-dimensional quantum correction frame for annealed crystalline LaAlO3/SrTiO3. These results clearly indicate that a large portion of electrons from oxygen vacancies are localized at low temperatures, serving as magnetic centers, while the electrons from the polar field are only weakly localized due to constructive interference between time-reversed electron paths in the clean limit and no signature of magnetic nature is visible.
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Affiliation(s)
- Xiaorong Zhou
- School of Materials Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Zhiqi Liu
- School of Materials Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
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Zhou B, Liang L, Ma J, Li J, Li W, Liu Z, Li H, Chen R, Li D. Thermally Assisted Rashba Splitting and Circular Photogalvanic Effect in Aqueously Synthesized 2D Dion-Jacobson Perovskite Crystals. NANO LETTERS 2021; 21:4584-4591. [PMID: 34037402 DOI: 10.1021/acs.nanolett.1c00364] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Recently, a two-dimensional Dion-Jacobson (DJ) perovskite (AMP)PbI4 (AMP = 4-(aminomethyl)piperidinium) is emerging with remarkable Rashba effect and ferroelectricity. However, the origin of the giant Rashba splitting remains elusive and the current synthetic strategy via slow cooling is time- and power-consuming, hindering its future applications. Here, we report on an economical aqueous method to obtain (AMP)PbI4 crystals and clarify the origin of the giant Rashba effect by temperature- and polarization-dependent photoluminescence (PL) spectroscopy. The strong temperature-dependent PL helicity indicates the thermally assisted structural distortion as the main origin of the Rashba effect, suggesting that valley polarization still preserves at high temperatures. The Rashba effect was further confirmed by the circular photogalvanic effect near the indirect bandgap. Our study not only optimizes the synthetic strategies of this DJ perovskite but also sheds light on its potential applications in room/high-temperature spintronics and valleytronics.
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Affiliation(s)
- Boxuan Zhou
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Lihan Liang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jiaqi Ma
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Junze Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Wancai Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zeyi Liu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Haolin Li
- Department of Electrical and Electronic Engineering Southern University of Science and Technology, Shenzhen, 518055, China
| | - Rui Chen
- Department of Electrical and Electronic Engineering Southern University of Science and Technology, Shenzhen, 518055, China
| | - Dehui Li
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China
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Sattar S, Larsson JA. Rashba Effect and Raman Spectra of Tl 2O/PtS 2 Heterostructure. ACS OMEGA 2021; 6:4044-4050. [PMID: 33585779 PMCID: PMC7876842 DOI: 10.1021/acsomega.0c06043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 01/12/2021] [Indexed: 06/12/2023]
Abstract
The possibility to achieve charge-to-spin conversion via Rashba spin-orbit effects provides stimulating opportunities toward the development of nanoscale spintronics. Here, we use first-principles calculations to study the electronic and spintronic properties of Tl2O/PtS2 heterostructure, for which we have confirmed the dynamical stability by its positive phonon frequencies. An unexpectedly high binding energy of -0.38 eV per unit cell depicts strong interlayer interactions between Tl2O and PtS2. Interestingly, we discover Rashba spin-splittings (with a large α R value) in the valence band of Tl2O stemming from interfacial spin-orbit effects caused by PtS2. The role of van der Waals binding on the orbital rearrangements has been studied using the electron localization function and atomic orbital projections, which explains in detail the electronic dispersion near the Fermi level. Moreover, we explain the distinct band structure alignment in momentum space but separation in real space of Tl2O/PtS2 heterostructure. Since two-dimensional (2D) Tl2O still awaits experimental confirmation, we calculate, for the first time, the Raman spectra of pristine Tl2O and the Tl2O/PtS2 heterostructure and discuss peak positions corresponding to vibrational modes of the atoms. These findings offer a promising avenue to explore spin physics for potential spintronics applications via 2D heterostructures.
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Zhao HJ, Nakamura H, Arras R, Paillard C, Chen P, Gosteau J, Li X, Yang Y, Bellaiche L. Purely Cubic Spin Splittings with Persistent Spin Textures. PHYSICAL REVIEW LETTERS 2020; 125:216405. [PMID: 33275000 DOI: 10.1103/physrevlett.125.216405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/10/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
Purely cubic spin splittings in the band structure of bulk insulators have not been extensively investigated yet despite the fact that they may pave the way for novel spin-orbitronic applications and can also result in a variety of promising spin phenomena. By symmetry analysis and first-principles simulations, we report symmetry-enforced purely cubic spin splittings (SEPCSS) that can even lead to persistent spin textures. In particular, these SEPCSS can be thought to be complementary to the cubic Rashba and cubic Dresselhaus types of spin splittings. Strikingly, the presently discovered SEPCSS are expected to exist in the large family of materials crystallizing in the 6[over ¯]m2 and 6[over ¯] point groups, including the Ge_{3}Pb_{5}O_{11}, Pb_{7}Br_{2}F_{12}, and Pb_{7}Cl_{2}F_{12} compounds.
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Affiliation(s)
- Hong Jian Zhao
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Hiro Nakamura
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Rémi Arras
- CEMES, Université de Toulouse, CNRS, UPS, 29 Rue Jeanne Marvig, F-31055 Toulouse, France
| | - Charles Paillard
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Laboratoire SPMS, CentraleSuplec/CNRS UMR8580, Université Paris-Saclay, 8-10 Rue Joliot-Curie, 91190 Gif-sur-Yvette, France
| | - Peng Chen
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Julien Gosteau
- CEMES, Université de Toulouse, CNRS, UPS, 29 Rue Jeanne Marvig, F-31055 Toulouse, France
| | - Xu Li
- Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Yurong Yang
- Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Laurent Bellaiche
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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11
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Ding J, Cheng J, Dogan F, Li Y, Lin W, Yao Y, Manchon A, Yang K, Wu T. Two-Dimensional Electron Gas at the Spinel/Perovskite Interface: Suppression of Polar Catastrophe by an Ultrathin Layer of Interfacial Defects. ACS APPLIED MATERIALS & INTERFACES 2020; 12:42982-42991. [PMID: 32829635 DOI: 10.1021/acsami.0c13337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional electron gas (2DEG) at the interface between two insulating perovskite oxides has attracted much interest for both fundamental physics and potential applications. Here, we report the discovery of a new 2DEG formed at the interface between spinel MgAl2O4 and perovskite SrTiO3. Transport measurements, electron microscopy imaging, and first-principles calculations reveal that the interfacial 2DEG is closely related to the symmetry breaking at the MgAl2O4/SrTiO3 interface. The critical film thickness for the insulator-to-metal transition is approximately 32 Å, which is twice as thick as that reported on the widely studied LaAlO3/SrTiO3 system. Scanning transmission electron microscopy imaging indicates the formation of interfacial Ti-Al antisite defects with a thickness of ∼4 Å. First-principles density functional theory calculations indicate that the coexistence of the antisite defects and surface oxygen vacancies may explain the formation of interfacial 2DEG as well as the observed critical film thickness. The discovery of 2DEG at the spinel/perovskite interface introduces a new material platform for designing oxide interfaces with desired characteristics.
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Affiliation(s)
- Junfeng Ding
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Jianli Cheng
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093-0448, United States
| | - Fatih Dogan
- College of Engineering and Technology, American University of the Middle East, Kuwait
| | - Yangyang Li
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Weinan Lin
- Department of Materials Science and Engineering, National University of Singapore, 117575 Singapore
| | - Yingbang Yao
- School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Aurelien Manchon
- Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
- Aix-Marseille Univ, CNRS, CINaM, Marseille 13288, France
| | - Kesong Yang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093-0448, United States
| | - Tom Wu
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, NSW 2052, Australia
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12
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Jana MK, Song R, Liu H, Khanal DR, Janke SM, Zhao R, Liu C, Valy Vardeny Z, Blum V, Mitzi DB. Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling. Nat Commun 2020; 11:4699. [PMID: 32943625 PMCID: PMC7499302 DOI: 10.1038/s41467-020-18485-7] [Citation(s) in RCA: 134] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/25/2020] [Indexed: 01/03/2023] Open
Abstract
Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chirality transfer across the organic-inorganic interface in two-dimensional hybrid perovskites using appropriate chiral organic cations. The preferred molecular configuration of the chiral spacer cations, R-(+)- or S-(-)-1-(1-naphthyl)ethylammonium and their asymmetric hydrogen-bonding interactions with lead bromide-based layers cause symmetry-breaking helical distortions in the inorganic layers, otherwise absent when employing a racemic mixture of organic spacers. First-principles modeling predicts a substantial bulk Rashba-Dresselhaus spin-splitting in the inorganic-derived conduction band with opposite spin textures between R- and S-hybrids due to the broken inversion symmetry and strong spin-orbit coupling. The ability to break symmetry using chirality transfer from one structural unit to another provides a synthetic design paradigm for emergent properties, including Rashba-Dresselhaus spin-polarization for hybrid perovskite spintronics and related applications.
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Affiliation(s)
- Manoj K Jana
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Ruyi Song
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
| | - Haoliang Liu
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
| | - Dipak Raj Khanal
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
| | - Svenja M Janke
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Rundong Zhao
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
| | - Chi Liu
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
| | - Z Valy Vardeny
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
| | - Volker Blum
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
| | - David B Mitzi
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708, USA.
- Department of Chemistry, Duke University, Durham, NC, 27708, USA.
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13
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Usachov DY, Nechaev IA, Poelchen G, Güttler M, Krasovskii EE, Schulz S, Generalov A, Kliemt K, Kraiker A, Krellner C, Kummer K, Danzenbächer S, Laubschat C, Weber AP, Sánchez-Barriga J, Chulkov EV, Santander-Syro AF, Imai T, Miyamoto K, Okuda T, Vyalikh DV. Cubic Rashba Effect in the Surface Spin Structure of Rare-Earth Ternary Materials. PHYSICAL REVIEW LETTERS 2020; 124:237202. [PMID: 32603174 DOI: 10.1103/physrevlett.124.237202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/13/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Spin-orbit interaction and structure inversion asymmetry in combination with magnetic ordering is a promising route to novel materials with highly mobile spin-polarized carriers at the surface. Spin-resolved measurements of the photoemission current from the Si-terminated surface of the antiferromagnet TbRh_{2}Si_{2} and their analysis within an ab initio one-step theory unveil an unusual triple winding of the electron spin along the fourfold-symmetric constant energy contours of the surface states. A two-band k·p model is presented that yields the triple winding as a cubic Rashba effect. The curious in-plane spin-momentum locking is remarkably robust and remains intact across a paramagnetic-antiferromagnetic transition in spite of spin-orbit interaction on Rh atoms being considerably weaker than the out-of-plane exchange field due to the Tb 4f moments.
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Affiliation(s)
- D Yu Usachov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
| | - I A Nechaev
- Department of Electricity and Electronics, FCT-ZTF, UPV-EHU, 48080 Bilbao, Spain
| | - G Poelchen
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - M Güttler
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - E E Krasovskii
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
| | - S Schulz
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A Generalov
- Max IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
| | - K Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - A Kraiker
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - C Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Strasse 1, D-60438 Frankfurt am Main, Germany
| | - K Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France
| | - S Danzenbächer
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - C Laubschat
- Institut für Festkörperphysik und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany
| | - A P Weber
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany
| | - E V Chulkov
- St. Petersburg State University, 7/9 Universitetskaya Naberezhnaya, St. Petersburg, 199034, Russia
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, 20080 Donostia/San Sebastián, Basque Country, Spain
- Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20018 Donostia/San Sebastián, Basque Country, Spain
- Tomsk State University, Lenina Avenue 36, 634050, Tomsk, Russia
| | - A F Santander-Syro
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - T Imai
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - K Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - T Okuda
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan
| | - D V Vyalikh
- Donostia International Physics Center (DIPC), 20018 Donostia/San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain
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14
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Ju W, Wang D, Li T, Zhang Y, Gao Z, Ren L, Li H, Gong S. Remarkable Rashba spin splitting induced by an asymmetrical internal electric field in polar III-VI chalcogenides. Phys Chem Chem Phys 2020; 22:9148-9156. [PMID: 32301938 DOI: 10.1039/d0cp00627k] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, the Rashba spin orbit coupling (SOC) of polar group III-VI chalcogenide XABY (A, B = Ga, In; X ≠ Y = S, Se, Te) monolayers is investigated based on density functional theory. The different electronegativities of X and Y atoms lead to an asymmetrical internal electric field in the XABY monolayer; this implies that the internal electric field between A and X is not equal to that between B and Y. Mirror symmetry breaking in the XABY monolayer induces a remarkable Rashba spin splitting (RSS) at the conduction band minimum (CBM). Moreover, it is demonstrated that an external electric field and an in-plane biaxial strain can affect the internal electric field by varying the charge distribution, and this further manipulates the RSS. Under a positive external electric field and tensile strain, the RSS at the CBM exhibits a near-linear increasing behavior, whereas under a negative external electric field and compressive strain, the RSS displays a monotonous decreasing pattern. In addition, we explored the influence of interlayer coupling and substrate on the RSS. The stacking pattern of bilayer structures has a significant impact on the RSS. The investigation of SInGaSe on the Si(111) substrate suggests that the Rashba band is situated inside the large band gap of the substrate. Overall, our investigations suggest that the polar group III-VI chalcogenides are promising candidates for future spintronic applications.
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Affiliation(s)
- Weiwei Ju
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China. and State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Donghui Wang
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Tongwei Li
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Yi Zhang
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Zijian Gao
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Lixian Ren
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Haisheng Li
- College of Physics and Engineering, Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications, Henan University of Science and Technology, Luoyang, 471023, China.
| | - Shijing Gong
- Department of Optoelectrics, East China Normal University, Shanghai 200062, China
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15
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Gu Y, Song C, Zhang Q, Li F, Tan H, Xu K, Li J, Saleem MS, Fayaz MU, Peng J, Hu F, Gu L, Liu W, Zhang Z, Pan F. Interfacial Control of Ferromagnetism in Ultrathin SrRuO 3 Films Sandwiched between Ferroelectric BaTiO 3 Layers. ACS APPLIED MATERIALS & INTERFACES 2020; 12:6707-6715. [PMID: 31927907 DOI: 10.1021/acsami.9b20941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Interfaces between materials provide an intellectually rich arena for fundamental scientific discovery and device design. However, the frustration of magnetization and conductivity of perovskite oxide films under reduced dimensionality is detrimental to their device performance, preventing their active low-dimensional application. Herein, by inserting the ultrathin 4d ferromagnetic SrRuO3 layer between ferroelectric BaTiO3 layers to form a sandwich heterostructure, we observe enhanced physical properties in ultrathin SrRuO3 films, including longitudinal conductivity, Curie temperature, and saturated magnetic moment. Especially, the saturated magnetization can be enhanced to ∼3.12 μB/Ru in ultrathin BaTiO3/SrRuO3/BaTiO3 trilayers, which is beyond the theoretical limit of bulk value (2 μB/Ru). This observation is attributed to the synergistic ferroelectric proximity effect (SFPE) at upper and lower BaTiO3/SrRuO3 heterointerfaces, as revealed by the high-resolution lattice structure analysis. This SFPE in dual-ferroelectric interface cooperatively induces ferroelectric-like lattice distortions in RuO6 oxygen octahedra and subsequent spin-state crossover in SrRuO3, which in turn accounts for the observed enhanced magnetization. Besides the fundamental significance of interface-induced spin-lattice coupling, our findings also provide a viable route to the electrical control of magnetic ordering, taking a step toward low-power applications in all-oxide spintronics.
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Affiliation(s)
- Youdi Gu
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Shenyang 110016 , China
| | - Cheng Song
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , China
| | - Fan Li
- Max Planck Institute for Microstructure Physics , Halle (Saale) D-06120 , Germany
| | - Hengxin Tan
- Max Planck Institute for Microstructure Physics , Halle (Saale) D-06120 , Germany
| | - Kun Xu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
| | - Jia Li
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , China
| | - Muhammad Shahrukh Saleem
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
| | - Muhammad Umer Fayaz
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
| | - Jingjing Peng
- Beijing Institute of Aeronautical Materials , Beijing 100095 , China
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics , Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Beijing 100190 , China
| | - Wei Liu
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Shenyang 110016 , China
| | - Zhidong Zhang
- Shenyang National Laboratory for Materials Science , Institute of Metal Research, University of Chinese Academy of Sciences, Chinese Academy of Sciences , Shenyang 110016 , China
| | - Feng Pan
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering , Tsinghua University , Beijing 100084 , China
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