Article
Physics, Multidisciplinary
Reena Yadav, Biplab Bhattacharyya, Animesh Pandey, Mandeep Kaur, Anurag Gupta, Sudhir Husale
Summary: This paper investigates the induced superconductivity in Bi2Se3 flakes through electric transport measurements in a hybrid structure composed of Bi2Se3 topological insulator thin flakes and tungsten (W) superconducting electrodes. The resistance of the flakes decreases significantly when the electrodes become superconducting, even when the length of the flakes exceeds the superconducting coherence length. Additionally, the magnetoresistance of the flakes changes from negative to positive above the transition temperature due to the effects of the superconducting electrodes.
Article
Materials Science, Multidisciplinary
Gilad Margalit, Binghai Yan, Marcel Franz, Yuval Oreg
Summary: In this study, we propose a novel heterostructure to achieve chiral topological superconductivity in a two-dimensional system. By bringing a substrate with a strong spin-orbit coupling energy close to thin films exfoliated from a high-temperature superconductor, and subjecting the combined system to an external magnetic field, we observe rare pairing symmetry and nontrivial topological properties.
Article
Materials Science, Multidisciplinary
S. K. Firoz Islam, A. Yu. Zyuzin, Alexander A. Zyuzin
Summary: We propose a theory of superconductivity in magic-angle twisted bilayer graphene and explore the superconducting phase diagram in the presence of a magnetic field. Our model involves a granular array hosting localized states that are hybridized with delocalized fermions in the intergrain regions. Under strong coupling, incoherent states with preformed Cooper pairs inside the grains are formed, while Andreev scattering between different grains leads to a globally phase-coherent superconducting state at lower temperatures. We find that the spin pair-breaking effect of an in-plane magnetic field can induce a new phase transition between the preformed Cooper pairing state and the Larkin-Ovchinnikov-Fulde-Ferrell state, and additionally enhances the upper critical magnetic field in the strong coupling case.
Article
Multidisciplinary Sciences
Daniel Pecak, Tomasz Sowinski
Summary: This study investigates attractively interacting two-component mixtures of fermionic particles confined in a one-dimensional harmonic trap and systematically explores the properties of balanced and imbalanced systems with finite-temperature effects. Specific non-classical pairing correlations are analyzed using single- and two-particle density distributions, and it is shown that imbalanced systems gradually transition into a standard Bardeen-Cooper-Schrieffer system characterized by zero net momentum of resulting pairs.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
Klaus Zollner, Jaroslav Fabian
Summary: Van der Waals heterostructures incorporating bilayer graphene within WS2 or CGT layers were studied, revealing the tunability of electronic spin properties through adjustments in twist angles and magnetization directions. Effective models based on fit parameters of model Hamiltonians were used to investigate the behavior under different configurations, providing insights for potential applications in spin transport and relaxation studies.
Article
Multidisciplinary Sciences
En Li, Jin-Xin Hu, Xuemeng Feng, Zishu Zhou, Liheng An, Kam Tuen Law, Ning Wang, Nian Lin
Summary: The authors demonstrate the emergence of multiple ultra-flat electronic bands in twisted bilayer WSe2 using scanning tunneling microscopy and spectroscopy, indicating the potential for further study of exotic correlated phases in TB-TMDs.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Applied
David Sanchez-Manzano, S. Mesoraca, F. Cuellar, M. Cabero, S. Rodriguez-Corvillo, V Rouco, F. Mompean, M. Garcia-Hernandez, J. M. Gonzalez-Calbet, C. Feuillet-Palma, N. Bergeal, J. Lesueur, C. Leon, Javier E. Villegas, J. Santamaria
Summary: The recent discovery of a long-range unconventional Josephson effect between YBa2Cu3O7 high Tc cuprates separated by a manganite ferromagnet has revealed a novel triplet proximity effect. The temperature dependence of the critical current in planar Josephson junctions was examined, and it was found that the behavior of the critical current follows the predictions of traditional superconductor-normal metal-superconductor junctions, suggesting that triplet pairs in a ferromagnet are transported similarly to singlet pairs in a normal metal. This result calls for theoretical studies of the new triplet Josephson effect and highlights its potential in future superconducting spintronics.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Jie Cao, Fenghua Qi, Hai Yang, Guojun Jin
Summary: The study focuses on the band structure and topological properties of twisted bilayer graphene at the first magic angle, finding that an external moire electric potential can further flatten the lowest energy bands to create a superflat band structure. These superflat bands promote the formation of Cooper pairs and increase the superconducting temperature, while a topological phase transition can be induced by modulating relevant parameters of the electric potential when combined with a boron nitride substrate.
Article
Materials Science, Multidisciplinary
Jonathan B. Curtis, Nicholas R. Poniatowski, Amir Yacoby, Prineha Narang
Summary: This study presents a platform for spectroscopic probing of unconventional superconductivity in thin-layer materials through the proximity effect. The observation of changes in collective modes and condensation provides insights into the pairing interactions and superconducting properties of the materials.
Article
Materials Science, Multidisciplinary
Kunihiro Yananose, Giovanni Cantele, Procolo Lucignano, Sang-Wook Cheong, Jaejun Yu, Alessandro Stroppa
Summary: The study found that twist chirality in twisted bilayer graphene induces changes in atomic displacement and spin textures, with different twist angles and chirality affecting the structure and properties.
Article
Chemistry, Physical
Yalin Zhang, Tong Wang, Zhihe Wang, Zhongwen Xing
Summary: The superconducting property induced by the proximity effect was observed in a topological-insulator/superconductor heterostructure, and it was found that the superconducting properties depend on the thicknesses of the layers.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Dionisios Margetis, Tobias Stauber
Summary: In this study, plasmonic edge modes for interfaces involving twisted bilayer graphene or similar moire van der Waals heterostructures are analytically described, emphasizing the influence of chiral response. The results suggest a universal dispersion function for optical edge plasmons in the paramagnetic regime, with implications for guiding future near-field nanoscopy.
Article
Materials Science, Multidisciplinary
Anurag Banerjee, Louis Haurie, Catherine Pepin
Summary: This paper investigates the proximity effects of charge density wave (CDW) on metals using the attractive Hubbard model. The authors demonstrate that periodic charge modulations develop in the metal due to the tunneling of finite momentum particle-hole pairs from the CDW region. The induced CDW produces a soft gap in the density of states, which can be detected in tunneling experiments.
Article
Materials Science, Multidisciplinary
Lucas Baldo, Tomas Lothman, Patric Holmvall, Annica M. Black-Schaffer
Summary: In this study, we investigate the effects of single, multiple, and extended defects in twisted bilayer graphene (TBG) on the behavior of the flat low-energy moire bands. We find that strong impurities and vacancies in the AA region lead to the complete removal of one moire band, resulting in a significant depletion of charge density. Other defect locations, except for the least coordinated sites in the AB region, result in a peculiar band replacement process within the moire bands. Triple-point fermions, appearing for single, periodic defects, are generally not preserved when adding extended or multiple defects.
Article
Multidisciplinary Sciences
Peter Rickhaus, Folkert K. de Vries, Jihang Zhu, Elias Portoles, Giulia Zheng, Michele Masseroni, Annika Kurzmann, Takashi Taniguchi, Kenji Watanabe, Allan H. MacDonald, Thomas Ihn, Klaus Ensslin
Summary: This study discovered a correlated electron-hole state in double-bilayer graphene twisted to 2.37 degrees, where moire states retain much of their isolated bilayer character. This allows the generation of an energetic overlap between narrow isolated electron and hole bands with good nesting properties, leading to the formation of ordered states with reconstructed Fermi surfaces consistent with a density-wave state that can be tuned without introducing chemical dopants.