Article
Materials Science, Multidisciplinary
L. N. Jiang, Yun-Peng Wang, Y. Zhu, X. F. Han
Summary: The long electrical screening length of an insulator allows changes in local ferroelectric polarization to affect the electrostatic potential across the entire insulating region, enhancing the tunneling electroresistance effect. First-principles calculations of multiferroic tunnel junctions reveal a unique local ferroelectric polarization at the interface, leading to an optimistic TER ratio.
Article
Chemistry, Multidisciplinary
Wenkai Zhu, Hailong Lin, Faguang Yan, Ce Hu, Ziao Wang, Lixia Zhao, Yongcheng Deng, Zakhar R. Kudrynskyi, Tong Zhou, Zakhar D. Kovalyuk, Yuanhui Zheng, Amalia Patane, Igor Zutic, Shushen Li, Houzhi Zheng, Kaiyou Wang
Summary: This study reports all-2D van der Waals vertical spin-valve devices with two distinct transport behaviors and reveals the critical role of pinholes in the magnetoresistance of such devices.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Physical
Keun-Hong Min, Duk Hyun Lee, Sang-Jun Choi, In-Ho Lee, Junho Seo, Dong Wook Kim, Kyung-Tae Ko, Kenji Watanabe, Takashi Taniguchi, Dong Han Ha, Changyoung Kim, Ji Hoon Shim, Jonghwa Eom, Jun Sung Kim, Suyong Jung
Summary: The authors investigate the tunnelling magnetoresistance in Fe3GeTe2/hBN(WSe2)/Fe3GeTe2 magnetic tunnel junctions and report strong variations including polarization reversals with bias. Using van der Waals heterostructures with two-dimensional magnets, they demonstrate electrically tunable spin injection and detection, as well as modulated and reversed net spin polarization of the injected carriers, leading to changes in tunnelling magnetoresistance. The authors attribute the spin polarization reversals to contributions from high-energy localized spin states in the metallic ferromagnet, which is inaccessible in conventional magnetic junctions.
Article
Multidisciplinary Sciences
Rui Guo, Lingling Tao, Ming Li, Zhongran Liu, Weinan Lin, Guowei Zhou, Xiaoxin Chen, Liang Liu, Xiaobing Yan, He Tian, Evgeny Y. Tsymbal, Jingsheng Chen
Summary: Although tunneling has been a known phenomenon in quantum mechanics, the deterministic control of electron and hole tunneling in tunnel junctions has provided new insights. Through interface engineering, electron and hole tunneling regimes can be controlled, offering new possibilities for the design functionality of electronic devices.
Article
Nanoscience & Nanotechnology
Jakub Pawlak, Witold Skowronski, Aritoni Zywczak, Marek Przybylski
Summary: This article discusses the magneto-transport properties of Fe/BTO/LSMO multiferroic tunnel junction, grown on a crystalline STO substrate, with specific focus on static, dynamic, and temperature-dependent behavior. The study shows high tunneling electroresistance and tunneling magnetoresistance in the MFTJ at room temperature. Temperature measurements reveal an exponential decrease in TMR with increasing temperature, while TER remains temperature independent. Electric ferromagnetic resonance measurements demonstrate the presence of two resonance peaks, attributed to LSMO and Fe, respectively.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Chemistry, Physical
Jin Yuan, Jian-Qing Dai, Miao-Wei Zhao
Summary: This study theoretically demonstrates that Pt/BiAlO3/Pt (Pt/BAO/Pt) structures can achieve a giant tunneling electroresistance (TER) effect, comparable to van der Waals tunnel junctions, by switching the electric polarization of the ferroelectric barrier. Furthermore, the use of a graphene monolayer can enhance the TER effect and improve the writing endurance of FTJ memories.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Natalia Andreeva, Anatoliy Petukhov, Oleg Vilkov, Adrian Petraru, Victor Luchinin
Summary: The study uses scanning tunneling spectroscopy in ultrahigh vacuum conditions and conductive atomic-force microscopy in ambient conditions to investigate the local electroresistive properties of ferroelectric tunnel junctions. The experimental current-voltage characteristics show dependence on the measurement technique applied, as the screening conditions of the polarization charges differ for the two scanning probe techniques. Additionally, the asymmetry of the tunnel barrier height for opposite ferroelectric polarization orientations may be influenced by the method used to study local tunnel electroresistance.
Article
Physics, Applied
Ang Li, Qinxuan Li, Caihong Jia, Weifeng Zhang
Summary: A study was conducted to distinguish the resistive switching mechanism between ferroelectric polarization switching and the normal resistive switching mechanism such as the drift or charge trapping of defects by growing BaTiO3 (BTO) thin films on a (001) Nb:SrTiO3 single crystal substrate using pulsed laser deposition. It was found that high energy samples with low defect density exhibited resistance hysteresis loops and little current hysteresis loops, while low energy samples with high defect density showed significant resistance and current hysteresis loops simultaneously.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Qinqin Wang, Ti Xie, Nicholas A. Blumenschein, Zhihao Song, Aubrey T. Hanbicki, Michael A. Susner, Benjamin S. Conner, Tony Low, Jian-Ping Wang, Adam L. Friedman, Cheng Gong
Summary: This study demonstrates high-performance FTJs constructed with graphene and a two-dimensional ferroelectric material, showing high tunneling electroresistance and gate tunability. This structure has potential applications in energy-efficient non-volatile memories and computing.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Hsin-Hui Huang, Yueh-Hua Chu, Tzu-Yun Wu, Ming-Hung Wu, I-Ting Wang, Tuo-Hung Hou
Summary: A comprehensive physical model is established to understand the device operation and optimization strategy of the ferroelectric tunnel junction. The model is capable of simulating various operations and has good agreement with experiments. The optimization strategy for the thickness of the ferroelectric layer and nonpolar interfacial layer is discussed, as well as the possible misinterpretation of measured results.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Ling Zhou, Junwei Huang, Ming Tang, Caiyu Qiu, Feng Qin, Caorong Zhang, Zeya Li, Di Wu, Hongtao Yuan
Summary: Magnetic tunnel junctions (MTJs) are spintronic devices based on the spin valve effect, and can be improved by utilizing advanced 2D ferromagnetic materials or exploring the gate-tunable magnetic properties. Recent research has shown that gate-tunable MTJ devices can be achieved by electrolyte gating, allowing for adjustable magnetoresistance ratio and magnetoresistance switching strength.
Article
Nanoscience & Nanotechnology
Yeong Jae Shin, Juan Jiang, Yichen Jia, Frederick J. Walker, Charles H. Ahn
Summary: BaTiO3 exhibits functional properties like high dielectric constant, large Pockels coefficient, and strong ferroelectricity/piezoelectricity, which can be used for various applications including non-volatile memory devices. Synthesis of BaTiO3 thin films by molecular beam epitaxy allows for growth of coherently strained and ferroelectric BaTiO3 at low temperatures, paving the way for large-scale integration with mainstream electronics platforms. Experimental results demonstrate surface mobility of BaO and TiO2 adatoms conducive to ferroelectric crystal growth at low temperatures.
Article
Materials Science, Multidisciplinary
Hui Gan, Shengchun Shen, Yaoxin Li, Yuewei Yin, Xiaoguang Li
Summary: We find that the electronic structures and transport properties of ferroelectric tunnel junctions (FTJs) are highly influenced by the types and locations of oxygen vacancies (OVs) in the ferroelectric barrier. The presence of OVs leads to the formation of local tail-to-tail domain walls, which alters the ferroelectricity of the barrier and the local density of states in the TiO2 layers. Consequently, the tunneling electroresistance (TER) effect is enhanced in the presence of OVs and is sensitive to their types and locations. These findings are crucial for the design of FTJs.
Article
Chemistry, Multidisciplinary
Kaifei Kang, Helmuth Berger, Kenji Watanabe, Takashi Taniguchi, Laszlo Forro, Jie Shan, Kin Fai Mak
Summary: Researchers have observed a thickness-driven 0-pi transition in Josephson junctions made of NbSe2 and Cr2Ge2Te6, and have also observed unusual supercurrent interference patterns near the critical thickness, indicating the formation of nanoscale domains in Cr2Ge2Te6.
Article
Chemistry, Multidisciplinary
Aitian Chen, Hong-Guang Piao, Minhui Ji, Bin Fang, Yan Wen, Yinchang Ma, Peisen Li, Xi-Xiang Zhang
Summary: The nonvolatile voltage control of resistance in Co/MgO/CoFeB magnetic tunnel junctions demonstrated in this study originates from the nonvolatile magnetization rotation of an interacting CoFeB magnet driven by volatile voltage-generated strain. The findings suggest that the magnetization response to volatile strain among interacting magnets is different from that among isolated magnets.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Kitae Eom, Hanjong Paik, Jinsol Seo, Neil Campbell, Evgeny Y. Tsymbal, Sang Ho Oh, Mark S. Rzchowski, Darrell G. Schlom, Chang-Beom Eom
Summary: This study reports the formation of 2-dimensional electron gases (2DEGs) with high mobility at room temperature at the LaScO3/BaSnO3 interface. By reducing the dislocation density and obtaining an atomically flat surface through specific treatment methods, an order of magnitude higher mobility at room temperature than previously achieved is achieved. This work opens up new possibilities for exploring the exciting physics of stannate-based 2DEGs at temperatures relevant to applications in oxide nanoelectronics.
Article
Chemistry, Multidisciplinary
Kai Huang, Ding-Fu Shao, Evgeny Y. Tsymbal
Summary: In this study, we demonstrate the electrical control of DMI and magnetic skyrmions in a Fe3GeTe2 monolayer through the ferroelectric polarization of an adjacent 2D vdW ferroelectric In2Se3. The results show that the magnitude and sign of DMI can be controlled by ferroelectric polarization reversal, leading to the creation and annihilation of skyrmions.
Article
Chemistry, Physical
Yu Yun, Pratyush Buragohain, Ming Li, Zahra Ahmadi, Yizhi Zhang, Xin Li, Haohan Wang, Jing Li, Ping Lu, Lingling Tao, Haiyan Wang, Jeffrey E. Shield, Evgeny Y. Tsymbal, Alexei Gruverman, Xiaoshan Xu
Summary: Ferroelectricity can be achieved in epitaxial HfO2 films with high structural order, indicating that it is an intrinsic property of HfO2-based materials. This discovery has significant implications for optimizing the performance of HfO2-based materials in device applications.
Article
Multidisciplinary Sciences
Shuai Hu, Ding-Fu Shao, Huanglin Yang, Chang Pan, Zhenxiao Fu, Meng Tang, Yumeng Yang, Weijia Fan, Shiming Zhou, Evgeny Y. Tsymbal, Xuepeng Qiu
Summary: Deterministic and field-free switching is demonstrated in a Ni/Co multilayer by exploiting the magnetic spin Hall effect in adjacent Mn3Sn, which is essential for low-power spintronics.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Simeon J. Gilbert, Hemian Yi, Tula Paudel, Alexey Lipatov, Andrew J. Yost, Alexander Sinitskii, Evgeny Y. Tsymbal, Jose Avila, Maria C. Asensio, Peter A. Dowben
Summary: The elemental contributions to the conduction bands of TiS3 and ZrS3 were examined using X-ray absorption spectroscopy, which showed that both compounds are mainly composed of hybridized transition metal-sulfur orbitals. However, the contribution of sulfur is different in each compound.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Correction
Engineering, Electrical & Electronic
Arnab Bose, Nathaniel J. Schreiber, Rakshit Jain, Ding-Fu Shao, Hari P. Nair, Jiaxin Sun, Xiyue S. Zhang, David A. Muller, Evgeny Y. Tsymbal, Darrell G. Schlom, Daniel C. Ralph
NATURE ELECTRONICS
(2022)
Article
Multidisciplinary Sciences
Zhongran Liu, Han Wang, Ming Li, Lingling Tao, Tula R. Paudel, Hongyang Yu, Yuxuan Wang, Siyuan Hong, Meng Zhang, Zhaohui Ren, Yanwu Xie, Evgeny Y. Tsymbal, Jingsheng Chen, Ze Zhang, He Tian
Summary: Domain-wall nanoelectronics is a new paradigm for non-volatile memory and logic technologies, where domain walls serve as an active element. Charged domain walls in ferroelectric structures have unique electronic and transport properties, which are useful for various nanoelectronics applications. In this study, a strategy for controllable creation and manipulation of charged domain walls in BiFeO3 ferroelectric films is reported, and their functionality as a memristor a few unit cells thick is demonstrated.
Article
Chemistry, Physical
Zifang Liu, Pengfei Hou, Lizhong Sun, Evgeny Y. Tsymbal, Jie Jiang, Qiong Yang
Summary: In this work, a two-dimensional van der Waals heterostructure composed of an alpha-In2Se3 ferroelectric and a hexagonal IV-VI semiconductor is designed, and an in-plane ferroelectric tunnel junction based on these heterostructures is proposed. First-principles calculations show that the electronic band structure of the designed heterostructures can be switched between insulating and metallic states by ferroelectric polarization. It is demonstrated that the in-plane ferroelectric tunnel junction exhibits two distinct transport regimes, tunneling and metallic, for OFF and ON states, respectively, resulting in a giant tunneling electroresistance effect with the OFF/ON resistance ratio exceeding 1 x 10(4). The results provide a promising approach for high-density ferroelectric memory based on 2D ferroelectric/semiconductor heterostructures.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Physics, Applied
Xinlu Li, Meng Zhu, Yaoyuan Wang, Fanxing Zheng, Jianting Dong, Ye Zhou, Long You, Jia Zhang
Summary: Recently, the research on van der Waals magnetic heterostructures in spintronics has increased. However, the lack of room-temperature magnetic order in vdW materials has hindered their practical development in spintronic devices. Inspired by the discovery of vdW ferromagnet Fe3GaTe2, which exhibits magnetic order above room temperature and significant perpendicular magnetic anisotropy, the electronic structure, magnetic properties, and tunneling magnetoresistance effect in magnetic tunnel junctions (MTJs) with Fe3GaTe2/insulator/Fe3GaTe2 structure were investigated using first-principles calculations. The results show that Fe3GaTe2-based MTJs have a prominent tunneling magnetoresistance effect at room temperature, comparable to conventional AlOx and MgO-based MTJs. This suggests that Fe3GaTe2-based MTJs could be a promising candidate for realizing long-awaited full magnetic vdW spintronic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
D. C. Mahendra, Ding-Fu Shao, Vincent D. -H. Hou, Arturas Vailionis, P. Quarterman, Ali Habiboglu, M. B. Venuti, Fen Xue, Yen-Lin Huang, Chien-Min Lee, Masashi Miura, Brian Kirby, Chong Bi, Xiang Li, Yong Deng, Shy-Jay Lin, Wilman Tsai, Serena Eley, Wei-Gang Wang, Julie A. Borchers, Evgeny Y. Tsymbal, Shan X. Wang
Summary: By utilizing unconventional spins generated in a MnPd3 thin film grown on an oxidized silicon substrate, the authors observed both conventional spin-orbit torques and unconventional out-of-plane and in-plane anti-damping-like torques in MnPd3/CoFeB heterostructures, enabling complete field-free switching of perpendicular cobalt. These unconventional torques are attributed to the low symmetry of the (114)-oriented MnPd3 films. The results provide a path towards practical spin channels in ultrafast magnetic memory and logic devices.
Article
Physics, Multidisciplinary
Haoying Sun, Jiahui Gu, Yongqiang Li, Tula R. Paudel, Di Liu, Jierong Wang, Yipeng Zang, Chengyi Gu, Jiangfeng Yang, Wenjie Sun, Zhengbin Gu, Evgeny Y. Tsymbal, Junming Liu, Houbing Huang, Di Wu, Yuefeng Nie
Summary: By applying uniaxial strain, we achieved pure in-plane polarized ferroelectricity in ultrathin SrTiO3 membranes, which allows for the investigation of ferroelectric size effects without the interference of the depolarization field. Our study reveals that the stability of ferroelectricity is influenced by the thickness-dependent dipole-dipole interactions within the transverse Ising model.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Shu Shi, Haolong Xi, Tengfei Cao, Weinan Lin, Zhongran Liu, Jiangzhen Niu, Da Lan, Chenghang Zhou, Jing Cao, Hanxin Su, Tieyang Zhao, Ping Yang, Yao Zhu, Xiaobing Yan, Evgeny Y. Tsymbal, He Tian, Jingsheng Chen
Summary: The authors demonstrate the stabilization of the metastable orthorhombic phase in Hf0.5 Zr0.5O2 films through interface engineering and hole doping.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Yuanxiang Zhang, Xinlu Li, Jichao Sheng, Shujie Yu, Jia Zhang, Yurong Su
Summary: This study investigates the spin-dependent transport in vdW MFTJs with a structure of Fe3GaTe2/bilayer alpha-In2Se3/Fe3GaTe2 using first-principles calculations. The results show that giant tunneling magnetoresistance and tunneling electroresistance can be achieved by controlling the magnetic alignments of Fe3GaTe2 and the ferroelectric configurations of bilayer alpha-In2Se3. The performance of MFTJs can be further enhanced by introducing interface asymmetry and inserting h-BN.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Xiaokun Wen, Wenyu Lei, Xinlu Li, Boyuan Di, Ye Zhou, Jia Zhang, Yuhui Zhang, Liufan Li, Haixin Chang, Wenfeng Zhang
Summary: Recent investigations have found that contacts made with conventional deposition processes using elemental semimetals (Bi and Sb) have the capability to approach the quantum limit in two-dimensional (2D) semiconductor contacts. This study demonstrates the use of a nondestructive van der Waals (vdW) transfer process to create novel compound Dirac semimetal ZrTe2 contacts to MoS2, which exhibit excellent ohmic contact characteristics and adjustable work functions.
Article
Materials Science, Multidisciplinary
Ding-Fu Shao, Shu-Hui Zhang, Rui-Chun Xiao, Zi-An Wang, W. J. Lu, Y. P. Sun, Evgeny Y. Tsymbal
Summary: In this study, we demonstrate the realization of a spin-neutral tunneling anomalous Hall effect (TAHE) in an antiferromagnetic (AFM) tunnel junction driven by spin-neutral currents. We show that the symmetry mismatch between the AFM electrode and the nonmagnetic barrier with strong spin-orbit coupling (SOC) results in spin-dependent momentum filtering, generating transverse Hall currents in each electrode. This finding opens up new possibilities for research in magnetoelectronics and spintronics.
