1
|
Chen B, Liu X, Li Y, Tay H, Taniguchi T, Watanabe K, Chan MHW, Yan J, Song F, Cheng R, Chang CZ. Even-Odd Layer-Dependent Exchange Bias Effect in MnBi 2Te 4 Chern Insulator Devices. NANO LETTERS 2024; 24:8320-8326. [PMID: 38935843 DOI: 10.1021/acs.nanolett.4c01597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Magnetic topological materials with coexisting magnetism and nontrivial band structures exhibit many novel quantum phenomena, including the quantum anomalous Hall effect, the axion insulator state, and the Weyl semimetal phase. As a stoichiometric layered antiferromagnetic topological insulator, thin films of MnBi2Te4 show fascinating even-odd layer-dependent physics. In this work, we fabricate a series of thin-flake MnBi2Te4 devices using stencil masks and observe the Chern insulator state at high magnetic fields. Upon magnetic field training, a large exchange bias effect is observed in odd but not in even septuple layer (SL) devices. Through theoretical calculations, we attribute the even-odd layer-dependent exchange bias effect to the contrasting surface and bulk magnetic properties of MnBi2Te4 devices. Our findings reveal the microscopic magnetic configuration of MnBi2Te4 thin flakes and highlight the challenges in replicating the zero magnetic field quantum anomalous Hall effect in odd SL MnBi2Te4 devices.
Collapse
Affiliation(s)
- Bo Chen
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and School of Physics, Nanjing University, Nanjing 210093, China
| | - Xiaoda Liu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yuhang Li
- School of Physics, Nankai University, Tianjin 300071, China
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, United States
| | - Han Tay
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jiaqiang Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and School of Physics, Nanjing University, Nanjing 210093, China
| | - Ran Cheng
- Department of Electrical and Computer Engineering, University of California, Riverside, California 92521, United States
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| |
Collapse
|
2
|
Shen B, Zhang JH, Liu Y, Ma J, Li Y, Hao X, Zhang R. Enhanced Absolute Recovered Energy under Low Electric Field in All-Inorganic 0-3 Nanocomposition Thick Films. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309486. [PMID: 38174606 DOI: 10.1002/smll.202309486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Inorganic thick-film dielectric capacitors with ultrahigh absolute recovered energy at low electric fields are extremely desired for their wide application in pulsed power systems. However, a long-standing technological bottleneck exists between high absolute energy and large recovered energy density. A new strategy is offered to fabricate selected all-inorganic 0-3 composite thick films up to 10 µm by a modified sol-slurry method. Here, the ceramic powder is dispersed into the sol-gel matrix to form a uniform suspension, assisted by powder, therefore, the 2 µm-thickness after single layer spin coating. To enhance the energy-storage performances, the composites process is thoroughly optimized by ultrafine powder (<50 nm) technique based on a low-cost coprecipitation method instead of the solid-state and sol-gel methods. 0D coprecipitation powder has a similar dielectric constant to the corresponding 3D films, thus uneven electrical field distributions is overcome. Moreover, the increase of interfacial polarization is realized due to the larger specific surface area. A maximum recoverable energy density of 14.62 J cm-3 is obtained in coprecipitation thick films ≈2.2 times that of the solid-state powder and ≈1.3 times for sol-gel powder. This study provides a new paradigm for further guiding the design of composite materials.
Collapse
Affiliation(s)
- Bingzhong Shen
- Functional Materials and Acousto-optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, P. R. China
| | - Jia-Han Zhang
- Collaborative Innovation Center of Advanced Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China
| | - Yang Liu
- Functional Materials and Acousto-optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, P. R. China
| | - Jinpeng Ma
- Functional Materials and Acousto-optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, P. R. China
| | - Yong Li
- Inner Mongolia Key Laboratory of Ferroelectric-Related New Energy Materials and Devices, Inner Mongolia University of Science and Technology, Baotou, 014010, P. R. China
| | - Xihong Hao
- Inner Mongolia Key Laboratory of Ferroelectric-Related New Energy Materials and Devices, Inner Mongolia University of Science and Technology, Baotou, 014010, P. R. China
| | - Rui Zhang
- Functional Materials and Acousto-optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, P. R. China
| |
Collapse
|
3
|
Mei R, Zhao YF, Wang C, Ren Y, Xiao D, Chang CZ, Liu CX. Electrically Controlled Anomalous Hall Effect and Orbital Magnetization in Topological Magnet MnBi_{2}Te_{4}. PHYSICAL REVIEW LETTERS 2024; 132:066604. [PMID: 38394580 DOI: 10.1103/physrevlett.132.066604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 12/22/2023] [Indexed: 02/25/2024]
Abstract
We propose an intrinsic mechanism to understand the even-odd effect, namely, opposite signs of anomalous Hall resistance and different shapes of hysteresis loops for even and odd septuple layers (SLs), of MBE-grown MnBi_{2}Te_{4} thin films with electron doping. The nonzero hysteresis loops in the anomalous Hall effect and magnetic circular dichroism for even-SLs MnBi_{2}Te_{4} films originate from two different antiferromagnetic (AFM) configurations with different zeroth Landau level energies of surface states. The complex form of the anomalous Hall hysteresis loop can be understood from two magnetic transitions, a transition between two AFM states followed by a second transition to the ferromagnetic state. Our model also clarifies the relationship and distinction between axion parameter and magnetoelectric coefficient, and shows an even-odd oscillation behavior of magnetoelectric coefficients in MnBi_{2}Te_{4} films.
Collapse
Affiliation(s)
- Ruobing Mei
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chong Wang
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Yafei Ren
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Di Xiao
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chao-Xing Liu
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| |
Collapse
|
4
|
Wang F, Zhao YF, Yan ZJ, Zhuo D, Yi H, Yuan W, Zhou L, Zhao W, Chan MHW, Chang CZ. Evolution of Dopant-Concentration-Induced Magnetic Exchange Interaction in Topological Insulator Thin Films. NANO LETTERS 2023; 23:2483-2489. [PMID: 36930727 DOI: 10.1021/acs.nanolett.2c03827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
To date, the quantum anomalous Hall effect has been realized in chromium (Cr)- and/or vanadium(V)-doped topological insulator (Bi,Sb)2Te3 thin films. In this work, we use molecular beam epitaxy to synthesize both V- and Cr-doped Bi2Te3 thin films with controlled dopant concentration. By performing magneto-transport measurements, we find that both systems show an unusual yet similar ferromagnetic response with respect to magnetic dopant concentration; specifically the Curie temperature does not increase monotonically but shows a local maximum at a critical dopant concentration. We attribute this unusual ferromagnetic response observed in Cr/V-doped Bi2Te3 thin films to the dopant-concentration-induced magnetic exchange interaction, which displays evolution from van Vleck-type ferromagnetism in a nontrivial magnetic topological insulator to Ruderman-Kittel-Kasuya-Yosida (RKKY)-type ferromagnetism in a trivial diluted magnetic semiconductor. Our work provides insights into the ferromagnetic properties of magnetically doped topological insulator thin films and facilitates the pursuit of high-temperature quantum anomalous Hall effect.
Collapse
Affiliation(s)
- Fei Wang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- School of Material Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zi-Jie Yan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Deyi Zhuo
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hemian Yi
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Wei Yuan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Lingjie Zhou
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Weiwei Zhao
- School of Material Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| |
Collapse
|
5
|
Fransson J. Vibrationally Induced Magnetism in Supramolecular Aggregates. J Phys Chem Lett 2023; 14:2558-2564. [PMID: 36877808 PMCID: PMC10026173 DOI: 10.1021/acs.jpclett.3c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Magnetic phenomena in chemistry and condensed matter physics are considered to be associated with low temperatures. That a magnetic state or order is stable below a critical temperature as well as becoming stronger the lower the temperature is a nearly unquestioned paradigm. It is, therefore, surprising that recent experimental observations made on supramolecular aggregates suggest that, for instance, the magnetic coercivity may increase with an increasing temperature and the chiral-induced spin selectivity effect may be enhanced. Here, a mechanism for vibrationally stabilized magnetism is proposed, and a theoretical model is introduced with which the qualitative aspects of the recent experimental findings can be explained. It is argued that anharmonic vibrations, which become increasingly occupied with an increasing temperature, enable nuclear vibrations to both stabilize and sustain magnetic states. The theoretical proposal, hence, pertains to structures without inversion and/or reflection symmetries, for instance, chiral molecules and crystals.
Collapse
|
6
|
Ale Crivillero MV, Rößler S, Granovsky S, Doerr M, Cook MS, Rosa PFS, Müller J, Wirth S. Magnetic and electronic properties unveil polaron formation in Eu[Formula: see text]In[Formula: see text]Sb[Formula: see text]. Sci Rep 2023; 13:1597. [PMID: 36709384 PMCID: PMC9884272 DOI: 10.1038/s41598-023-28711-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/23/2023] [Indexed: 01/30/2023] Open
Abstract
The intermetallic compound Eu[Formula: see text]In[Formula: see text]Sb[Formula: see text], an antiferromagnetic material with nonsymmorphic crystalline structure, is investigated by magnetic, electronic transport and specific heat measurements. Being a Zintl phase, insulating behavior is expected. Our thermodynamic and magnetotransport measurements along different crystallographic directions strongly indicate polaron formation well above the magnetic ordering temperatures. Pronounced anisotropies of the magnetic and transport properties even above the magnetic ordering temperature are observed despite the Eu[Formula: see text] configuration which testify to complex and competing magnetic interactions between these ions and give rise to intricate phase diagrams discussed in detail. Our results provide a comprehensive framework for further detailed study of this multifaceted compound with possible nontrivial topology.
Collapse
Affiliation(s)
| | - Sahana Rößler
- Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| | - S. Granovsky
- Institute for Solid State and Materials Physics, Technical University Dresden, 01062 Dresden, Germany
| | - M. Doerr
- Institute for Solid State and Materials Physics, Technical University Dresden, 01062 Dresden, Germany
| | - M. S. Cook
- Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | | | - J. Müller
- Institute of Physics, Goethe-University Frankfurt, 60438 Frankfurt (M), Germany
| | - S. Wirth
- Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany
| |
Collapse
|
7
|
From Quantum Materials to Microsystems. MATERIALS 2022; 15:ma15134478. [PMID: 35806603 PMCID: PMC9267837 DOI: 10.3390/ma15134478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/21/2022] [Accepted: 06/21/2022] [Indexed: 12/04/2022]
Abstract
The expression “quantum materials” identifies materials whose properties “cannot be described in terms of semiclassical particles and low-level quantum mechanics”, i.e., where lattice, charge, spin and orbital degrees of freedom are strongly intertwined. Despite their intriguing and exotic properties, overall, they appear far away from the world of microsystems, i.e., micro-nano integrated devices, including electronic, optical, mechanical and biological components. With reference to ferroics, i.e., functional materials with ferromagnetic and/or ferroelectric order, possibly coupled to other degrees of freedom (such as lattice deformations and atomic distortions), here we address a fundamental question: “how can we bridge the gap between fundamental academic research focused on quantum materials and microsystems?”. Starting from the successful story of semiconductors, the aim of this paper is to design a roadmap towards the development of a novel technology platform for unconventional computing based on ferroic quantum materials. By describing the paradigmatic case of GeTe, the father compound of a new class of materials (ferroelectric Rashba semiconductors), we outline how an efficient integration among academic sectors and with industry, through a research pipeline going from microscopic modeling to device applications, can bring curiosity-driven discoveries to the level of CMOS compatible technology.
Collapse
|