Article
Physics, Multidisciplinary
Shuchun Huan, Shihao Zhang, Zhicheng Jiang, Hao Su, Hongyuan Wang, Xin Zhang, Yichen Yang, Zhengtai Liu, Xia Wang, Na Yu, Zhiqiang Zou, Dawei Shen, Jianpeng Liu, Yanfeng Guo
Summary: In this study, we reveal that MnSb4Te7 is a magnetic topological system with versatile topological phases that can be manipulated by both carrier doping and magnetic field. This introduces a new magnetic topological material with different topological phases that are highly tunable by carrier doping or magnetic field.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Minkyung Kim, Zihao Wang, Yihao Yang, Hau Tian Teo, Junsuk Rho, Baile Zhang
Summary: Researchers have designed and demonstrated a 3D photonic topological insulator (PTI) that exhibits self-guided topological surface states without the need for additional confinement. By removing spin-orbit coupling, this PTI opens new possibilities for manipulating photons at the outer surface of photonic bandgap materials.
NATURE COMMUNICATIONS
(2022)
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
Rui Yu, Jie Feng Cao, Xiang Yu Meng, Fang Yuan Zhu, Jun Qin Li, Ge Xing Qu, Yao Bo Huang, Yong Wang, Ren Zhong Tai
Summary: This study demonstrates the controllable charge-spin conversion efficiency in topological insulators by manipulating the ferroelectric polarization, with an enhancement of up to about 450%. The efficiency is mainly influenced by the evolution of the band structure under strain modulation.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Multidisciplinary Sciences
Alexander J. Breindel, Yuhang Deng, Camilla M. Moir, Yuankan Fang, Sheng Ran, Hongbo Lou, Shubin Li, Qiaoshi Zeng, Lei Shu, Christian T. Wolowiec, Ivan K. Schuller, Priscila F. S. Rosa, Zachary Fisk, John Singleton, M. Brian Maple
Summary: This article reports the study of the conductive surface state (CSS) and bulk phase properties of FeSi, and finds that a CSS exists below 19K. Comparison with the Kondo insulator SmB6 reveals similar behavior in magnetoresistance and energy gap changes between the two materials.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Optics
Christian Heide, Yuki Kobayashi, Denitsa R. Baykusheva, Deepti Jain, Jonathan A. Sobota, Makoto Hashimoto, Patrick S. Kirchmann, Seongshik Oh, Tony F. Heinz, David A. Reis, Shambhu Ghimire
Summary: Researchers have found that circularly polarized laser-field-driven high-harmonic generation is highly sensitive to the non-trivial and trivial topological phases in topological insulators. By chemically reducing the spin-orbit interaction strength, the phase transition between non-trivial and trivial topological states can be achieved. This purely optical method offers sensitivity to the electronic structure of the material and is compatible with a wide range of samples and sample environments.
Article
Chemistry, Multidisciplinary
E. Rongione, L. Baringthon, D. She, G. Patriarche, R. Lebrun, A. Lemaitre, M. Morassi, N. Reyren, M. Micica, J. Mangeney, J. Tignon, F. Bertran, S. Dhillon, P. Le Fevre, H. Jaffres, J. -m. George
Summary: By combining spin- and angle-resolved photoemission spectroscopy with time-resolved THz emission spectroscopy, it is demonstrated that spin-charge conversion mainly arises from the surface state in ultrathin films of Bi1-xSbx. The robustness of the surface state and the significant conversion efficiency in epitaxial Bi1-xSbx thin films bring new perspectives for ultra-low power magnetic random-access memories and broadband THz generation.
Article
Physics, Multidisciplinary
J. Dai, E. Frantzeskakis, N. Aryal, K-W Chen, F. Fortuna, J. E. Rault, P. Le Fevre, L. Balicas, K. Miyamoto, T. Okuda, E. Manousakis, R. E. Baumbach, A. F. Santander-Syro
Summary: We report the observation of a nontrivial spin texture in Dirac node arcs, which are novel topological objects formed when Dirac cones of massless particles extend along an open one-dimensional line in momentum space. These states are present in all compounds of the tetradymite M2Te2X family, regardless of the strength of the topological invariant. Thus, the Dirac node arcs in tetradymites represent the simplest type-I Dirac system with a single spin-polarized node arc.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Yuefeng Yin, Chutian Wang, Michael S. Fuhrer, Nikhil Medhekar
Summary: Tuning the interaction between the bulk and edge states of topological materials is a powerful tool for manipulating edge transport behavior in planar bismuthene. By exploring the impact of various perturbation effects, such as device size, substrate potentials, and applied transverse electric field, the electronic structure and edge transport in planar bismuthene can be engineered to exhibit either a gapped or conducting unconventional helical spin texture. These results open up new directions for discovering novel spin transport patterns in topological materials and provide critical insights for the fabrication of topological spintronic devices.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Jin Zhang, Nicolas Tancogne-Dejean, Lede Xian, Emil Vinas Bostrom, Martin Claassen, Dante M. Kennes, Angel Rubio
Summary: Laser-induced ultrafast demagnetization is an interesting phenomenon with significant implications in ultrafast optoelectronics and spintronics. The spin response is found to depend on the laser wavelength and polarization due to electron correlations, band renormalizations, and charge redistributions.
Article
Multidisciplinary Sciences
Anuva Aishwarya, Zhuozhen Cai, Arjun Raghavan, Marisa Romanelli, Xiaoyu Wang, Xu Li, G. D. Gu, Mark Hirsbrunner, Taylor Hughes, Fei Liu, Lin Jiao, Vidya Madhavan
Summary: Incorporating relativistic physics into quantum tunneling can lead to exotic behavior such as perfect transmission through Klein tunneling. In this study, tunneling properties of spin-momentum-locked relativistic fermions were probed using nanowires made of the topological Kondo insulator candidate samarium hexaboride. The nanowires were attached to scanning tunneling microscope tips to image the bicollinear stripe spin order in the antiferromagnet Fe1.03Te with a Neel temperature of about 50 kelvin.
Article
Physics, Multidisciplinary
Daniel Leykam, Daria A. Smirnova
Summary: Topological invariants characterizing filled bands in electronic materials cannot be directly applied to bosonic systems. Instead, the topological invariants in bosonic systems can be determined by transitions from bound to leaky modes in photonic lattices.
Article
Multidisciplinary Sciences
Yoshiyuki Ohtsubo, Toru Nakaya, Takuto Nakamura, Patrick Le Fevre, Francois Bertran, Fumitoshi Iga, Shin-Ichi Kimura
Summary: The breakdown of in-plane rotation symmetry in topological surface states (TSSs) of SmB6 is shown to be related to the importance of surface atomic structure. Experimentally, it is found that TSSs are anisotropic and lack the fourfold rotation symmetry observed in the bulk on the SmB6(001)-p(2 x 2) surface. These results suggest that engineering the surface atomic structure could provide a new pathway to tailor various properties of TSSs.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
Julian F. Wienand, Friederike Horn, Monika Aidelsburger, Julian Bibo, Fabian Grusdt
Summary: This research demonstrates that quantized Thouless pumps connecting C-4-symmetric higher-order topological phases of matter can be described by a tuple of four Chern numbers, which measure quantized bulk charge transport in a direction-dependent manner and allows for the prediction of the sign and value of fractional corner charges. Additionally, the study reveals that the topologically nontrivial phase can be characterized by both quadrupole and dipole configurations.
PHYSICAL REVIEW LETTERS
(2022)
Article
Nanoscience & Nanotechnology
J. M. Brevoord, D. H. Wielens, M. Lankhorst, J. Diez-Merida, Y. Huang, C. Li, A. Brinkman
Summary: Experimental configuration was tested to probe fractional charge and phase interference effect, with good agreement between experimental results and numerical simulations. Phase interference effect was observed in superconducting arrays, but no clear sign of axion charge-related interference effect was observed. Discussions on possible reasons and perspectives for future experiments were provided.
Article
Physics, Multidisciplinary
B. Q. Lv, Alfred Zong, D. Wu, A. V. Rozhkov, Boris V. Fine, Su-Di Chen, Makoto Hashimoto, Dong-Hui Lu, M. Li, Y. -B. Huang, Jacob P. C. Ruff, Donald A. Walko, Z. H. Chen, Inhui Hwang, Yifan Su, Xiaozhe Shen, Xirui Wang, Fei Han, Hoi Chun Po, Yao Wang, Pablo Jarillo-Herrero, Xijie Wang, Hua Zhou, Cheng-Jun Sun, Haidan Wen, Zhi-Xun Shen, N. L. Wang, Nuh Gedik
Summary: We report an unconventional hysteretic transition in a quasi-2D material, EuTe4, with a hysteresis loop of more than 400K temperature width, setting a record among crystalline solids. The origin of this transition lies entirely within the incommensurate charge density wave (CDW) phase of EuTe4, without any change in the CDW modulation periodicity. We interpret the hysteresis as an unusual switching of the relative CDW phases in different layers, unique to quasi-2D compounds.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Emre Ergecen, Batyr Ilyas, Dan Mao, Hoi Chun Po, Mehmet Burak Yilmaz, Junghyun Kim, Je-Geun Park, T. Senthil, Nuh Gedik
Summary: This study reveals the bound states of d-orbitals and phonons in 2D vdW antiferromagnet NiPS3 through ultrafast spectroscopy. These states manifest as equally spaced phonon replicas in the frequency domain and become observable with magnetic order. The electronic origin of the bound states is established as localized d-d excitations through the emission and spectral tracking of phonons.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Qian Song, Connor A. Occhialini, Emre Ergecen, Batyr Ilyas, Danila Amoroso, Paolo Barone, Jesse Kapeghian, Kenji Watanabe, Takashi Taniguchi, Antia S. Botana, Silvia Picozzi, Nuh Gedik, Riccardo Comin
Summary: This article reports the discovery of type-II multiferroic order in a single atomic layer of the transition-metal-based van der Waals material NiI2. The multiferroic state of NiI2 is characterized by a proper-screw spin helix that induces chirality-controlled electrical polarization. Through various optical measurements and theoretical simulations, it is found that NiI2 has a highly anisotropic electronic state that breaks both rotational and inversion symmetry, supporting polar order. Interestingly, the ordered magnetic polar state persists down to the monolayer level of NiI2. These findings introduce a new platform for studying emergent multiferroic phenomena, chiral magnetic textures, and ferroelectricity in the realm of two-dimensional van der Waals materials.
Article
Chemistry, Inorganic & Nuclear
Juyeon Won, Soyeun Kim, Martin Gutierrez-Amigo, Simon Bettler, Bumjoo Lee, Jaeseok Son, Tae Won Noh, Ion Errea, Maia G. Vergniory, Peter Abbamonte, Fahad Mahmood, Daniel P. Shoemaker
Summary: In this study, the single crystal growth of Ag3AuSe2 and its transport and optical properties were investigated. The results showed that Ag3AuSe2 is a highly resistive semiconductor with a band gap and activation energy of approximately 0.3 eV. First-principles calculations suggested that the experimentally determined band gap lies between the predicted band gaps from GGA and hybrid functionals. Band inversion was predicted to be possible under tensile strain. Further investigation is needed to understand the effects of Ag/Au ordering, chemical substitution, and heat treatment on the band gap.
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
(2022)
Article
Surgery
Raheel Ahmad, Marco Baia, David N. Naumann, Fahad Mahmood, Fabio Tirotta, Samuel Ford, Anant Desai, Max Almond
Summary: Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare malignancy, and the diagnosis and treatment during pregnancy require consideration of the risks to both the mother and the fetus. This article reports a case of SPN identified during pregnancy, with surgery delayed until the fetus reached near-term. Postpartum surgical management was required due to complications.
JOURNAL OF SURGICAL CASE REPORTS
(2022)
Article
Multidisciplinary Sciences
Faran Zhou, Kyle Hwangbo, Qi Zhang, Chong Wang, Lingnan Shen, Jiawei Zhang, Qianni Jiang, Alfred Zong, Yifan Su, Marc Zajac, Youngjun Ahn, Donald A. Walko, Richard D. Schaller, Jiun-Haw Chu, Nuh Gedik, Xiaodong Xu, Di Xiao, Haidan Wen
Summary: This study reveals the existence of a spin-shear coupling mechanism in van der Waals antiferromagnetic materials, where subtle shear can have a profound effect on magnetic order. Experimental results identify interlayer shear as the primary structural degree of freedom that couples with magnetic order, allowing for ultrafast control of magnetic order through spin-mechanical coupling.
NATURE COMMUNICATIONS
(2022)
Review
Cardiac & Cardiovascular Systems
Marco Baia, David N. Naumann, Chee S. Wong, Fahad Mahmood, Alessandro Parente, Daniele Bissacco, Max Almond, Samuel J. Ford, Fabio Tirotta, Anant Desai
Summary: This systematic review summarizes the current evidence regarding the surgical management of the inferior vena cava (IVC) in cases of involvement in neoplastic processes. Different surgical techniques and strategies are required depending on the type and location of the tumor. A multidisciplinary approach with specialist expertise is necessary to achieve the best overall survival.
JOURNAL OF CARDIOVASCULAR SURGERY
(2022)
Article
Chemistry, Physical
Soyeun Kim, Yinchuan Lv, Xiao-Qi Sun, Chengxi Zhao, Nina Bielinski, Azel Murzabekova, Kejian Qu, Ryan A. Duncan, Quynh L. D. Nguyen, Mariano Trigo, Daniel P. Shoemaker, Barry Bradlyn, Fahad Mahmood
Summary: Using time-domain terahertz emission spectroscopy, we observe coherent and narrowband terahertz radiation emitted from (TaSe4)(2)I material under transient photoexcitation at low temperatures, indicating the existence of a phason coupled to long-range Coulomb interactions. These findings highlight the role of long-range interactions in determining the nature of collective excitations in materials with modulated charge or spin order.
Article
Surgery
Sivesh K. Kamarajah, Marco Baia, David N. Naumann, Fahad Mahmood, Alessandro Parente, Max Almond, Fabio Tirotta, Samuel J. Ford, Fadi Dahdaleh, Anant Desai
Article
Medicine, General & Internal
Adewale Ayeni, Fahad Mahmood, Ameer Mustafa, Bethan Mcleish, Vaibhavi Kulkarni, Shika Singhal, Akinfemi Akingboye
Summary: This retrospective study aimed to investigate the use of Platelet-to-Lymphocyte Ratio (PLR) and Neutrophil-to-Lymphocyte Ratio (NLR) as markers for distinguishing uncomplicated (UA) and complicated appendicitis (CA) in children. The results showed that NLR and PLR are reliable, synergistic markers predicting complicated appendicitis, which can guide non-operative management in children.
CUREUS JOURNAL OF MEDICAL SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Junbo Zhu, Changmin Lee, Fahad Mahmood, Takehito Suzuki, Shiang Fang, Nuh Gedik, Joseph G. Checkelsky
Summary: In this study, we investigated the transport, thermodynamic, and spectroscopic properties of ZrTe5 to understand its band structure and unique thermoelectric properties. We observed a small electronic band gap and temperature dependent Fermi level in this material. The thermoelectric coefficients of ZrTe5 showed an unusually large and nonmonotonic temperature evolution. Additionally, we found a significant enhancement of the thermoelectric coefficients in a magnetic field. These findings provide a comprehensive understanding of ZrTe5 as a high mobility small Fermi surface system with potential for magnetic field driven thermoelectricity.
Article
Materials Science, Multidisciplinary
Fahad Mahmood, David Ingram, Xi He, J. A. Clayhold, Ivan Bozovic, N. P. Armitage
Summary: Using time-domain terahertz spectroscopy and mutual inductance measurements, this study investigates the low-energy electrodynamic response of overdoped La2-xSrxCuO4 films exposed to ion irradiation. The results show that the transport scattering rate is directly proportional to the radiation dose at all temperatures, and the relationship between Tc, the superfluid density, and the scattering rates in the superconducting state is different from the predictions based on existing theories.
Article
Medicine, General & Internal
Viswa R. Rajalingam, Ameer Mustafa, Adewale Ayeni, Fahad Mahmood, Sarah Shammout, Shikha Singhal, Akinfemi Akingboye
Summary: This study aims to investigate the use of PLR and/or NLR as a surrogate biomarker in differentiating uncomplicated from complicated appendicitis. The results showed that NLR and PLR are reliable surrogate biomarkers for assessing the severity of acute appendicitis.
CUREUS JOURNAL OF MEDICAL SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Fahad Mahmood, Thomas Devereaux, Peter Abbamonte, Dirk K. Morr
Summary: This study shows that double photoemission can be used to identify the pairing state in superconductors and provides direct insight into the center-of-mass momentum and spin state of the superconducting condensate, thus distinguishing between different superconducting pairing states. In addition, double photoemission can be used to map out the momentum dependence of the superconducting order parameter.
