Article
Multidisciplinary Sciences
Jingyuan Zhong, Ming Yang, Zhijian Shi, Yaqi Li, Dan Mu, Yundan Liu, Ningyan Cheng, Wenxuan Zhao, Weichang Hao, Jianfeng Wang, Lexian Yang, Jincheng Zhuang, Yi Du
Summary: Weak topological insulators with tunable topological states are studied using ARPES and first-principles calculations. The authors find signatures of layer-selective quantum spin Hall channels in a candidate weak topological insulator, Bi4Br2I2, which is stacked by three different quantum spin Hall insulators. The energy gap at the crossing points of different Dirac cones, induced by interlayer interaction, enables the tunability of topological edge states. This work offers a perspective for constructing tunable quantized conductance devices for future spintronic applications.
NATURE COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Dima Sadek, Daya S. Dhungana, Roland Coratger, Corentin Durand, Arnaud Proietti, Quentin Gravelier, Benjamin Reig, Emmanuelle Daran, Pier Francesco Fazzini, Fuccio Cristiano, Alexandre Arnoult, Sebastien R. Plissard
Summary: The bismuth-antimony alloy is the first reported 3D topological insulator with promising potential for spintronic applications. This work successfully demonstrates the integration of high-quality rhombohedral BiSb topological insulators on a GaAs substrate, showcasing epitaxial relationship and relaxed TI layer growth.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Nana Shumiya, Md Shafayat Hossain, Jia-Xin Yin, Zhiwei Wang, Maksim Litskevich, Chiho Yoon, Yongkai Li, Ying Yang, Yu-Xiao Jiang, Guangming Cheng, Yen-Chuan Lin, Qi Zhang, Zi-Jia Cheng, Tyler A. Cochran, Daniel Multer, Xian P. Yang, Brian Casas, Tay-Rong Chang, Titus Neupert, Zhujun Yuan, Shuang Jia, Hsin Lin, Nan Yao, Luis Balicas, Fan Zhang, Yugui Yao, M. Zahid Hasan
Summary: This study provides micro-spectroscopic evidence for the presence of a room-temperature quantum spin Hall edge state on the surface of a higher-order topological insulator. The research reveals the microstructural features of the topological phase and suggests further exploration of high-temperature transport quantization.
Article
Materials Science, Multidisciplinary
Xuguang Wang, Daiyu Geng, Dayu Yan, Wenqi Hu, Hexu Zhang, Shaosheng Yue, Zhenyu Sun, Shiv Kumar, Eike F. Schwier, Kenya Shimada, Peng Cheng, Lan Chen, Simin Nie, Zhijun Wang, Youguo Shi, Yi-Qi Zhang, Kehui Wu, Baojie Feng
Summary: Experimental evidence of a 2DTI in the van der Waals material Ta2Pd3Te5 has been reported, showing that each monolayer is a 2DTI with weak interlayer interactions. Measurements confirm the existence of a band gap at the Fermi level and topological edge states inside the gap, making Ta2Pd3Te5 a promising material for fabricating spintronic devices based on the QSH effect.
Article
Materials Science, Multidisciplinary
T. Nathan Nunley, Side Guo, Liang-Juan Chang, David Lujan, Jeongheon Choe, Shang-Fan Lee, Fengyuan Yang, Xiaoqin Li
Summary: Recent research has found that thulium iron garnet (TmIG) based bilayers show promise in realizing small skyrmions at room temperature. By directly measuring the magnetic hysteresis loops, researchers have determined that the spin Hall topological Hall resistivity is considerably larger than previously estimated values. This finding further confirms the existence of skyrmions at room temperature and near-zero applied magnetic fields.
Article
Engineering, Mechanical
Yafeng Chen, Jensen Li, Jie Zhu
Summary: A topology optimization approach was developed for designing second-order phononic topological insulators based on the quantum spin Hall effect, resulting in the creation of phononic crystals with record-breaking size of overlapped bandgap. The optimized PCs were successfully used to create SPTIs arranged by hexagon and rhombus unit cells, validating the effectiveness of the optimization results. Additionally, the spatial decay of corner states was quantitatively characterized based on complex band theory, bridging topology optimization with SPTIs and enriching the understanding of corner states.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Xiangting Hu, Ning Mao, Hao Wang, Ying Dai, Baibiao Huang, Chengwang Niu
Summary: The study demonstrates that the QSH phase can survive under antiferromagnetic long-range order in a RbCuSe/CsMnP heterobilayer, exhibiting topological nontrivial features. The role of effective spin-orbit coupling and antiferromagnetism is discussed to reveal the underlying physical mechanism. These findings may lead to advancements in topological magnetism and antiferromagnetic spintronics.
Article
Materials Science, Multidisciplinary
Y. Kinoshita, T. Fujita, R. Kurihara, A. Miyake, Y. Izaki, Y. Fuseya, M. Tokunaga
Summary: In the presence of high magnetic fields, enhanced electronic correlation effects stabilize anomalous quantum states. With band-tuning using a magnetic field, we achieved a spin-polarized quantum-limit state in the field-induced semimetallic phase of a topological insulator Bi1-xSbx. Increasing the field further injects more electrons and holes into this state, resulting in an unexpected reentrant insulator state in this topological semimetallic phase. This reentrant insulator state cannot be explained by a single-particle picture and resembles phase transitions driven by many-body effects. Estimates based on binding energy, electron-hole pair spacing, and thermal de Broglie wavelength suggest the possible existence of the excitonic insulator phase in Bi1-xSbx under extreme conditions.
Article
Chemistry, Multidisciplinary
Xiaodong Zhou, Wanxiang Feng, Yinwei Li, Yugui Yao
Summary: In this study, the emergence of spin-chirality-driven quantum anomalous Hall effect (QAHE) and quantum topological Hall effect (QTHE) is demonstrated by sandwiching a 2D Z(2) topological insulator between two chiral kagome antiferromagnetic single-layers. The QAHE is realized with fully compensated noncollinear antiferromagnetism instead of conventional collinear ferromagnetism. The Chern number can be regulated periodically with the interplay between vector- and scalar-spin chiralities, and the QAHE can even occur without spin-orbit coupling, indicating the rare QTHE. These findings open up a new avenue for antiferromagnetic quantum spintronics based on unconventional mechanisms from chiral spin textures.
Article
Chemistry, Physical
Hao Tang, Ariel Rebekah Barr, Guoqing Wang, Paola Cappellaro, Ju Li
Summary: Spin qubits associated with color centers show promise for various quantum technologies, but their intrinsic properties need to be known precisely under external conditions such as temperature and strain. This research develops a first-principles method to determine the temperature dependence of color centers' properties and demonstrates its accuracy with the NV-center in diamond. This method can be applied to different color centers and is useful for designing high-precision quantum sensors.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Physics, Multidisciplinary
Shihao Zhang, Xi Dai, Jianpeng Liu
Summary: In this study, we theoretically investigate correlated insulator states and quantum anomalous Hall states in twisted multilayer graphene systems. We show that these systems can exhibit spin-polarized and valley-polarized insulator states under different interactions, and these states can be manipulated by external forces.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Yi-Ping Wang, He Wang
Summary: We propose a theoretical method to study the topological properties of spin-phonon coupled modes in a one-dimensional superconducting resonator lattice. Different topological structures can be displayed by adjusting the coupling parameters, and the topological index of the system's phases can be distinguished.
QUANTUM INFORMATION PROCESSING
(2023)
Article
Physics, Multidisciplinary
Zhejunyu Jin, Xianglong Yao, Zhenyu Wang, H. Y. Yuan, Zhaozhuo Zeng, Weiwei Wang, Yunshan Cao, Peng Yan
Summary: It has been discovered that hidden nonlinear magnon transport in magnetic textures can generate fictitious magnetic fields. By analyzing the scattering features between magnons and skyrmions, a significant Hall angle in both confluence and splitting modes has been predicted, and it has been found that the Hall angle reverses its sign when switching the handedness of the incident magnons. This finding may open up new possibilities for probing gauge fields through nonlinear means.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Applied
Ivan I. Naumov, Pratibha Dev
Summary: Chemical modifications and stacking of layered crystals can create novel phases of matter. Ab initio computations show the realization of a unique state in a bismuth nanoribbon decorated with nitrogen atoms, where quantum spin Hall state coexists with ferromagnetism due to short-range exchange interactions. The coexistence is robust and can even occur when the nanoribbon is placed on a substrate or without passivation with nitrogen atoms in a heterostructure.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Rui Wang, Tigran A. Sedrakyan, Baigeng Wang, Lingjie Du, Rui-Rui Du
Summary: Correlation and frustration are important in physics, leading to new quantum phases. In this study, we observe the moat-band phenomena in shallowly inverted InAs/GaSb quantum wells, where we find an unconventional time-reversal-symmetry breaking excitonic ground state. We demonstrate the evolution from helical-like to chiral-like edge transport and explain our experimental observations using a moat band for excitons that results from density imbalance.
Article
Multidisciplinary Sciences
Liang-Ying Feng, Rovi Angelo B. Villaos, Aniceto B. Maghirang, Zhi-Quan Huang, Chia-Hsiu Hsu, Hsin Lin, Feng-Chuan Chuang
Summary: Through the study of Zintl compounds CaM2X2, it was discovered that CaM2Bi2 (M = Zn or Cd) is a new type of topological crystalline insulator with four-fold degenerate Dirac points. These findings provide a new field for the search of new topological materials.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Applied
Marku Nyevel R. Perez, Rovi Angelo B. Villaos, Liang-Ying Feng, Aniceto B. Maghirang III, Chih-Peng Cheng, Zhi-Quan Huang, Chia-Hsiu Hsu, Arun Bansil, Feng-Chuan Chuang
Summary: Recent first-principles calculations explore the stability and topological properties of Zintl single-quintuple-layer compounds in the CaAl2Si2 structure. The study reveals insulating topological phases driven by band inversion and the possibility of coexisting insulating and superconducting topological phases. The synthesis of these compounds through atomic substitutions is also discussed.
APPLIED PHYSICS REVIEWS
(2022)
Article
Nanoscience & Nanotechnology
Daniel J. Trainer, Jouko Nieminen, Fabrizio Bobba, Baokai Wang, Xiaoxing Xi, Arun Bansil, Maria Iavarone
Summary: In this study, the authors investigated common point defects in monolayer MoS2 using low-temperature scanning tunneling microscopy and spectroscopy. They identified the defects as molybdenum vacancies based on their characteristic in-gap resonances. The study also revealed the role of the substrate in the band structure of defective MoS2 monolayers.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Bahadur Singh, Hsin Lin, Arun Bansil
Summary: Interest in topological materials is growing due to their conceptual novelty and potential for transformative new technologies. This perspective presents recent research on understanding the role of geometry and topology in generating topological states and their responses. Effective strategies for topological materials discovery and future research directions are also discussed.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yuita Fujisawa, Markel Pardo-Almanza, Chia-Hsiu Hsu, Atwa Mohamed, Kohei Yamagami, Anjana Krishnadas, Guoqing Chang, Feng-Chuan Chuang, Khoong Hong Khoo, Jiadong Zang, Anjan Soumyanarayanan, Yoshinori Okada
Summary: Through systematic investigation of epitaxial Cr1+delta Te2 thin films, it is revealed that this magnetic transition metal dichalcogenide exhibits momentum-space Berry curvature effects conducive to spin-based topological phenomena, and its electron filling can be tuned through doping. Spectroscopic experiments and transport experiments demonstrate the presence of a characteristic semi-metallic band region and the change in the intrinsic component of the anomalous Hall effect, respectively. Density functional theory calculations establish a link between the doping evolution of the band structure and the anomalous Hall effect.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Jian-Xiang Qiu, Christian Tzschaschel, Junyeong Ahn, Anyuan Gao, Houchen Li, Xin-Yue Zhang, Barun Ghosh, Chaowei Hu, Yu-Xuan Wang, Yu-Fei Liu, Damien Berube, Thao Dinh, Zhenhao Gong, Shang-Wei Lien, Sheng-Chin Ho, Bahadur Singh, Kenji Watanabe, Takashi Taniguchi, David C. Bell, Hai-Zhou Lu, Arun Bansil, Hsin Lin, Tay-Rong Chang, Brian B. Zhou, Qiong Ma, Ashvin Vishwanath, Ni Ni, Su-Yang Xu
Summary: Using circularly polarized light, researchers have observed helicity-dependent optical control of fully compensated antiferromagnetic order in a topological axion insulator called MnBi2Te4. This optical control and circular dichroism are based on the optical axion electrodynamics and can potentially be used to control PT-symmetric antiferromagnets and create dissipationless circuits using topological edge states.
Article
Multidisciplinary Sciences
Anyuan Gao, Yu-Fei Liu, Jian-Xiang Qiu, Barun Ghosh, Thais V. Trevisan, Yugo Onishi, Chaowei Hu, Tiema Qian, Hung-Ju Tien, Shao-Wen Chen, Mengqi Huang, Damien Berube, Houchen Li, Christian Tzschaschel, Thao Dinh, Zhe Sun, Sheng-Chin Ho, Shang-Wei Lien, Bahadur Singh, Kenji Watanabe, Takashi Taniguchi, David C. Bell, Hsin Lin, Tay-Rong Chang, Chunhui Rita Du, Arun Bansil, Liang Fu, Ni Ni, Peter P. Orth, Qiong Ma, Su-Yang Xu
Summary: This article reports a quantum metric nonlinear Hall effect induced by interfacing even-layered MnBi2Te4 with black phosphorus. The effect switches direction upon reversing the antiferromagnetic spins and exhibits distinct scaling.
Review
Chemistry, Analytical
Phuong V. Pham, The-Hung Mai, Huy-Binh Do, Vinoth Kumar Ponnusamy, Feng-Chuan Chuang
Summary: This article provides an overview of the applications of graphene heterostructure devices in optical sensing and optoelectronics. It discusses the use of graphene heterostructures in various systems such as ultrafast optical sensing, plasmonic systems, optical waveguides, optical spectrometers, and optical synaptic systems. The article also highlights important research on improving the performance and stability of graphene heterostructures and reveals their pros and cons, as well as the synthesis and nanofabrication sequences in optoelectronics.
Article
Materials Science, Multidisciplinary
Hung-Yu Yang, Jonathan Gaudet, Rahul Verma, Santu Baidya, Faranak Bahrami, Xiaohan Yao, Cheng-Yi Huang, Lisa DeBeer-Schmitt, Adam A. Aczel, Guangyong Xu, Hsin Lin, Arun Bansil, Bahadur Singh, Fazel Tafti
Summary: We investigate the magnetic and electronic transport properties of NdAlGe, a Weyl semimetal which breaks inversion and time-reversal symmetries. The material displays an incommensurate spin density wave and transitions to a commensurate ferrimagnetic state at low temperatures. Small-angle neutron scattering reveals the formation of ferrimagnetic domains with different characteristic length scales in real space. Interestingly, unlike NdAlSi, NdAlGe exhibits two different regimes of anomalous Hall effect, one governed by intrinsic Berry curvature and the other by extrinsic disorders/spin fluctuations.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Hao-Jen You, Bo-Ying Su, Yi-Ting Chiang, Tse-Hsiao Li, Hsu-Shen Chu, Hsin Lin
Summary: The thermoelectric properties of n-type doped Sr2Si and Sr2Ge were investigated using first-principles density functional theory calculations and semi-classical Boltzmann transport theory. The multi-band feature in the conduction band of Sr2Ge leads to a higher Seebeck coefficient, resulting in a higher power factor. The phonon transport calculations predict ultra-low lattice thermal conductivity for both materials, with a maximum figure of merit of 1.44 for Sr2Ge at 900 K.
MATERIALS TODAY PHYSICS
(2023)
Article
Physics, Multidisciplinary
Christopher Lane, Ruiqi Zhang, Bernardo Barbiellini, Robert S. Markiewicz, Arun Bansil, Jianwei Sun, Jian-Xin Zhu
Summary: The discovery of superconductivity in doped infinite-layer nickelates has attracted significant attention. The authors used a quantum many-body approach to investigate the electronic and magnetic properties of LaNiO2, providing insights into the suppressed long-range order and magnetic excitation spectrum in the nickelates. They found that the magnetic properties of the infinite-layer nickelates are closer to those of doped cuprates, rather than undoped cuprates. The study gives insights into the origin of strong magnetic competition in the infinite-layer nickelates and their relationship with the cuprates.
COMMUNICATIONS PHYSICS
(2023)
Article
Multidisciplinary Sciences
Sathya R. Chitturi, Zhurun Ji, Alexander N. Petsch, Cheng Peng, Zhantao Chen, Rajan Plumley, Mike Dunne, Sougata Mardanya, Sugata Chowdhury, Hongwei Chen, Arun Bansil, Adrian Feiguin, Alexander I. Kolesnikov, Dharmalingam Prabhakaran, Stephen M. Hayden, Daniel Ratner, Chunjing Jia, Youssef Nashed, Joshua J. Turner
Summary: This research utilizes a machine learning platform combined with linear spin wave theory simulations to extract and optimize advanced models for ordered magnetic systems using inelastic neutron scattering data. It provides a framework for real-time analysis of experimental data in condensed matter.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Jinwoong Kim, Cheng-Yi Huang, Hsin Lin, David Vanderbilt, Nicholas Kioussis
Summary: The researchers propose that pristine bulk Bi can serve as a three-dimensional analog of the SSH model, demonstrating the existence of topologically nontrivial and trivial domain walls and providing criteria for determining the Zak phase of domain walls based on parity eigenvalues. They suggest that the dimerization reversal in Bi and the formation of domain walls can be achieved through intense femtosecond laser excitations.
Article
Materials Science, Multidisciplinary
Debasis Dutta, Barun Ghosh, Bahadur Singh, Hsin Lin, Antonio Politano, Arun Bansil, Amit Agarwal
Summary: Plasmonics in topological semimetals provide opportunities for fundamental physics exploration and technological applications. We found two distinct plasmon modes in CoSi with different dispersions and long lifetimes.
Article
Materials Science, Multidisciplinary
Ruiqi Zhang, Cheng-Yi Huang, Jamin Kidd, Robert S. Markiewicz, Hsin Lin, Arun Bansil, Bahadur Singh, Jianwei Sun
Summary: This paper reports the discovery of a topological state with pseudonodal surface and double-Weyl fermions in cerium hexaboride (CeB6). By analyzing the electronic states, the researchers find protected band crossings in CeB6 and predict a giant anomalous Hall conductivity.
