Article
Quantum Science & Technology
Arthur Leis, Michael Schleenvoigt, Vasily Cherepanov, Felix Luepke, Peter Schueffelgen, Gregor Mussler, Detlev Gruetzmacher, Bert Voigtlaender, F. Stefan Tautz
Summary: This study investigated the transport properties of (Bi0.16Sb0.84)2Te3 films across a quantum phase transition, revealing an exponential drop in conductivity below the critical thickness, indicating the presence of spin-conserving backscattering.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Materials Science, Multidisciplinary
E. Rongione, S. Fragkos, L. Baringthon, J. Hawecker, E. Xenogiannopoulou, P. Tsipas, C. Song, M. Micica, J. Mangeney, J. Tignon, T. Boulier, N. Reyren, R. Lebrun, P. Le Fevre, S. Dhillon, A. Dimoulas, H. Jaffres, M. George
Summary: This study demonstrates sizable terahertz (THz) emission through a nanometric thick topological insulator (TI)/ferromagnetic junction. By employing terahertz emission time domain spectroscopy (TDS), the contribution of topological surface states (TSS) to spin-to-charge conversion (SCC) is investigated, highlighting the significance of this approach for studying interfacial spintronic properties.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
James H. H. Cullen, Rhonald Burgos Atencia, Dimitrie Culcer
Summary: Spin torques at topological insulator (TI)/ferromagnet interfaces have been studied to achieve electrical control of magnetic degrees of freedom. The relative contributions of bulk and surface states to spin torque are still not fully understood. In this study, the authors investigate the spin torques due to TI bulk states and find that there is no spin-orbit torque on a homogeneous magnetisation from the bulk states, unlike the surface states which give rise to a spin-orbit torque. The authors also discover a spin transfer torque due to the inhomogeneity of the magnetisation near the interface, which has not been considered before in TIs.
Article
Chemistry, Multidisciplinary
Federico Binda, Stefano Fedel, Santos Francisco Alvarado, Paul Noel, Pietro Gambardella
Summary: The study investigates the spin-orbit torques (SOTs) and spin Hall magnetoresistance generated by Bi0.9Sb0.1(0001) when coupled with FeCo, confirming its effectiveness as a spin-injector material. The research finds that charge-to-spin conversion in single-crystal Bi0.9Sb0.1(0001) is isotropic despite the strong anisotropy of the topological surface states. Additionally, the damping-like SOT displays non-monotonic temperature dependence, with a minimum occurring at 20 K.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Areg Ghazaryan, Emilian M. Nica, Onur Erten, Pouyan Ghaemi
Summary: The study investigates the unique surface states of topological Kondo insulators (TKIs) that support surface states with arbitrarily large Fermi surfaces when the chemical potential is pinned to the Dirac point, leading to finite-frequency quantum oscillations. The researchers demonstrate the mechanism and significance of shadow surface states in tetragonal TKIs, providing an important example of high-frequency quantum oscillations beyond cubic TKIs.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Applied
Peng Liu, Hangyu Li, Zhitao Zhou, Yongmao Pei
Summary: This study provides experimental verification of pseudo-spin states on the boundary of an acoustic topological insulator using acoustic particle manipulation, revealing the characteristics of the pseudo-spin sound field and its potential application in controlling particle rotation.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
N. V. Leppenen, L. E. Golub
Summary: The theory of the linear photogalvanic effect in three-dimensional topological insulators is discussed. Both the shift contribution caused by coordinate shifts and the ballistic contribution caused by optical absorption and scattering have the same magnitude. The ballistic contribution dominates in the nonlinear regime due to saturation of direct optical transitions. This distinction is important for experiments.
Article
Physics, Multidisciplinary
Ari M. Turner, Erez Berg, Ady Stern
Summary: In this study, the stability of fragile topological bands protected by space-time inversion symmetry under strong electron-electron interactions is investigated. It is found that when these fragile bands are half filled, interactions can open a gap in the many-body spectrum without breaking any symmetry or mixing degrees of freedom from remote bands. The resulting ground state is not topologically ordered. The formation of fermionic bound states known as trions is crucial for this result, which may be relevant to recent experiments in magic angle twisted bilayer graphene at charge neutrality.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Yu Fu, Jing Li, Jules Papin, Paul Noel, Salvatore Teresi, Maxen Cosset-Cheneau, Cecile Grezes, Thomas Guillet, Candice Thomas, Yann-Michel Niquet, Philippe Ballet, Tristan Meunier, Jean-Philippe Attane, Albert Fert, Laurent Vila
Summary: Spin-orbit effects in topological insulators and at Rashba interfaces have led to various newly discovered effects. In this study, a bilinear magnetoresistance phenomenon was observed in strained HgTe, and its amplitude and sign could be controlled by adjusting the contributions from opposite surfaces using an electric gate.
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
Matheus I. N. Rosa, Massimo Ruzzene, Emil Prodan
Summary: Twisted bilayered systems exhibit higher dimensional topological phases and 4D integer quantum Hall effect, which can be accessed by sliding the layers relative to each other.
COMMUNICATIONS PHYSICS
(2021)
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
Chemistry, Multidisciplinary
Polina M. Sheverdyaeva, Conor Hogan, Gustav Bihlmayer, Jun Fujii, Ivana Vobornik, Matteo Jugovac, Asish K. Kundu, Sandra Gardonio, Zipporah Rini Benher, Giovanni Di Santo, Sara Gonzalez, Luca Petaccia, Carlo Carbone, Paolo Moras
Summary: Topological insulators are bulk insulators with metallic and fully spin-polarized surface states exhibiting Dirac-like band dispersion. By using spin-resolved photoemission spectroscopy, we show that the topological surface states of a topological insulator interfaced with an antimonene bilayer exhibit nearly full out-of-plane spin polarization within the substrate gap. This phenomenon is connected to a symmetry-protected band crossing of the spin-polarized surface states. The nearly full out-of-plane spin polarization of the topological surface states occurs along a continuous path in the energy-momentum space, and the spin polarization within the gap can be reversibly tuned from nearly full out-of-plane to nearly full in-plane by electron doping. These findings pave the way for advanced spintronics applications that exploit the giant out-of-plane spin polarization of topological surface states.
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
Vipin Vijayan, L. Chotorlishvili, A. Ernst, S. S. P. Parkin, M. I. Katsnelson, S. K. Mishra
Summary: In a two-dimensional helical spin lattice, the presence of a quantum skyrmionic phase is observed. This topological phase remains stable over a large parameter space before transitioning to a ferromagnetic phase. The stability is enhanced and the topological phase is shifted in the parameter space due to the influence of next-nearest-neighbor interaction. Nonanalytic behavior in the rate function indicates a dynamical quantum phase transition when the system undergoes a quench from the quantum skyrmion phase to a trivial quantum ferromagnetic phase, while no dynamical quantum phase transition is observed when the system quenches from the skyrmion phase to a helical phase.