المؤلفون: Mallik, Srijani, Göbel, Börge, Witt, Hugo, Vicente-Arche, Luis M., Varotto, Sara, Bréhin, Julien, Ménard, Gerbold, Saïz, Guilhem, Tamsaout, Dyhia, Santander-Syro, Andrés Felipe, Fortuna, Franck, Bertran, François, Fèvre, Patrick Le, Rault, Julien, Boventer, Isabella, Mertig, Ingrid, Barthélémy, Agnès, Bergeal, Nicolas, Johansson, Annika, Bibes, Manuel

مصطلحات موضوعية: Condensed Matter - Materials Science

الوصف: Two-dimensional electron gases(2DEGs)based on KTaO3 are emerging as a promising platform for spin-orbitronics due to their high Rashba spin-orbit coupling (SOC) and gate-voltage tunability. The recent discovery of a superconducting state in KTaO3 2DEGs now expands their potential towards topological superconductivity. Although the band structure of KTaO3 surfaces of various crystallographic orientations has already been mapped using angle-resolved photoemission spectroscopy(ARPES), this is not the case for superconducting KTaO3 2DEGs. Here, we reveal the electronic structure of superconducting 2DEGs based on KTaO3 (111) single crystals through ARPES measurements. We fit the data with a tight-binding model and compute the associated spin textures to bring insight into the SOC-driven physics of this fascinating system.
Comment: 9 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/2311.08230Test

المؤلفون: Andres Santander-Syro, Fortuna Franck, Franck Fortuna, Kairi Morozumi, Rodel Tobias, Santander-Syro Andrés, Shik Shin, Tobias Rodel, Toshiyuki Taniuchi, Yoshihito Motoyui, 両角 海里, 元結 啓仁, 谷内 敏之, 辛 埴

المصدر: JSAP Annual Meetings Extended Abstracts. 2016, :1338

المؤلفون: Andres Felipe Santander Syro, Cleassen Ralph, Fortuna Franck, Franck Fortuna, Michael Sing, Philipp Scheiderer, Ralph Cleassen, Rödel Tobias C., Santander Syro Andrés Felipe, Scheiderer Philipp, Shik Shin, Sing Michael, Tobias C. Rodel, Toshiyuki Taniuchi, Yoshihito Motoyui, 元結 啓仁, 谷内 敏之, 辛 埴

المصدر: JSAP Annual Meetings Extended Abstracts. 2015, :79

المؤلفون: Carlot Gaëlle, Sabathier Catherine, Maillard Serge, Michel Amélie, Martin Guillaume, Gilabert Eric, Fortuna Franck, Garcia Philippe

المصدر: EPJ Web of Conferences, Vol 115, p 03003 (2016)

مصطلحات موضوعية: Physics, QC1-999

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2100-014XTest

الوصول الحر: https://doaj.org/article/c1e238a013344e31acf98ba90eb8e2faTest

المؤلفون: Frantzeskakis, Emmanouil, Dai, Ji, Bareille, Cédric, Rödel, Tobias C., Güttler, Monika, Ran, Sheng, Kanchanavatee, Noravee, Huang, Kevin, Pouse, Naveen, Wolowiec, Christian T., Rienks, Emile D. L., Lejay, Pascal, Fortuna, Franck, Maple, M. Brian, Santander-Syro, Andrés F.

المصدر: PNAS 118, e2020750118 (2021)

مصطلحات موضوعية: Condensed Matter - Strongly Correlated Electrons

الوصف: In matter, any spontaneous symmetry breaking induces a phase transition characterized by an order parameter, such as the magnetization vector in ferromagnets, or a macroscopic many-electron wave-function in superconductors. Phase transitions with unknown order parameter are rare but extremely appealing, as they may lead to novel physics. An emblematic, and still unsolved, example is the transition of the heavy fermion compound URu$_2$Si$_2$ (URS) into the so-called hidden-order (HO) phase when the temperature drops below $T_0 = 17.5$K. Here we show that the interaction between the heavy fermion and the conduction band states near the Fermi level has a key role in the emergence of the HO phase. Using angle resolved photoemission spectroscopy, we find that while the Fermi surfaces of the HO and of a neighboring antiferromagnetic (AFM) phase of well-defined order parameter have the same topography, they differ in the size of some, but not all, of their electron pockets. Such a non-rigid change of the electronic structure indicates that a change in the interaction strength between states near the Fermi level is a crucial ingredient for the HO-to-AFM phase transition.
Comment: 23 pages, 14 figures, 1 ancillary movie

الوصول الحر: http://arxiv.org/abs/2107.03872Test

المؤلفون: Sengupta, Shamashis, Monteverde, Miguel, Murani, Anil, Marrache-Kikuchi, Claire, Santander-Syro, Andres F., Fortuna, Franck

المصدر: Phys. Rev. B 105, 125112 (2022)

مصطلحات موضوعية: Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons

الوصف: Two-dimensional electron gases in SrTiO3-based heterostructures provide a platform to study the real-time evolution of the macroscopic state with a variation of the carrier density, and the impact of structural properties on the emergence of the superconducting state. We have explored the isothermal evolution of the electron gas in AlOx/SrTiO3 by measuring the variation of resistance with continuous gate-voltage-controlled tuning of its carrier density. It is seen that condensation of the ordered phase leads to non-monotonic isotherms within the superconducting dome. The timescale for dynamic change following changes in gate voltage is measured across the phase transition. It is found to be tens of seconds near the onset of superconductivity, significantly larger compared to the normal state. Such a large timescale governing the kinetics of the phase transition presumably arises from the strong impact of structural defects and distortions of the substrate on the development of superconducting islands.

الوصول الحر: http://arxiv.org/abs/2104.03633Test

المؤلفون: Rödel, Tobias Chris, Fortuna, Franck, Sengupta, Shamashis, Frantzeskakis, Emmanouil, Fèvre, Patrick Le, Bertran, François, Mercey, Bernard, Matzen, Sylvia, Agnus, Guillaume, Maroutian, Thomas, Lecoeur, Philippe, Felipe~Santander-Syro, Andrés

المصدر: Adv. Mater. 28, 1976-1980 (2016)

مصطلحات موضوعية: Condensed Matter - Strongly Correlated Electrons

الوصف: Two-dimensional electron systems (2DESs) in functional oxides are promising for applications, but their fabrication and use, essentially limited to SrTiO$_3$-based heterostructures, are hampered by the need of growing complex oxide over-layers thicker than 2~nm using evolved techniques. This work shows that thermal deposition of a monolayer of an elementary reducing agent suffices to create 2DESs in numerous oxides.
Comment: Main Text + Supporting Information, 25 pages, 11 figures

الوصول الحر: http://arxiv.org/abs/2102.07748Test

المؤلفون: Jaouen Nicolas, Tortarolo Marina, Delaunay Renaud, Fortuna Franck, Popescu Horia, Spezzani Carlo, Sacchi Maurizio

المصدر: EPJ Web of Conferences, Vol 40, p 01001 (2013)

مصطلحات موضوعية: Physics, QC1-999

الوصف: We performed x-ray holography experiments using synchrotron radiation. By analyzing the scattering of coherent circularly polarized x-rays tuned at the Co-2p resonance, we imaged perpendicular magnetic domains in a Co/Pd multilayer. We compare results obtained for continuous and laterally confined films.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2100-014XTest

الوصول الحر: https://doaj.org/article/61ca1d232a054533a2c2972dd8f47d65Test

المؤلفون: Sengupta, Shamashis, Tisserond, Emilie, Linez, Florence, Monteverde, Miguel, Murani, Anil, Rödel, Tobias, Lecoeur, Philippe, Maroutian, Thomas, Marrache-Kikuchi, Claire, Santander-Syro, Andrés F., Fortuna, Franck

المصدر: Journal of Applied Physics 124, 213902 (2018)

مصطلحات موضوعية: Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics

الوصف: Electronic properties of low dimensional superconductors are determined by many-body-effects. This physics has been studied traditionally with superconducting thin films, and in recent times with two-dimensional electron gases (2DEGs) at oxide interfaces. In this work, we show that a superconducting 2DEG can be generated by simply evaporating a thin layer of metallic Al under ultra-high vacuum on a SrTiO3 crystal, whereby Al oxidizes into amorphous insulating alumina, doping the SrTiO3 surface with oxygen vacancies. The superconducting critical temperature of the resulting 2DEG is found to be tunable with a gate voltage with a maximum value of 360 mK. A gate-induced switching between superconducting and resistive states is demonstrated. Compared to conventionally-used pulsed-laser deposition (PLD), our work simplifies to a large extent the process of fabricating oxide-based superconducting 2DEGs. It will make such systems accessible to a broad range of experimental techniques useful to understand low-dimensional phase transitions and complex many-body-phenomena in electronic systems.
Comment: 15 pages, 5 figures

الوصول الحر: http://arxiv.org/abs/1810.08069Test

المؤلفون: Lömker, Patrick, Rödel, Tobias C., Gerber, Timm, Fortuna, Franck, Frantzeskakis, Emmanouil, Fèvre, Patrick Le, Bertran, François, Müller, Martina, Santander-Syro, Andrés F.

المصدر: Phys. Rev. Materials 1, 062001(R) (2017)

مصطلحات موضوعية: Condensed Matter - Materials Science

الوصف: We create a two-dimensional electron system (2DES) at the interface between EuO, a ferromagnetic insulator, and SrTiO3, a transparent non-magnetic insulator considered the bedrock of oxide-based electronics. This is achieved by a controlled in-situ redox reaction between pure metallic Eu deposited at room temperature on the surface of SrTiO3, an innovative bottom-up approach that can be easily generalized to other functional oxides and scaled to applications. Additionally, we find that the resulting EuO capping layer can be tuned from paramagnetic to ferromagnetic, depending on the layer thickness. These results demonstrate that the simple, novel technique of creating 2DESs in oxides by deposition of elementary reducing agents [T. C. R\"odel et al., Adv. Mater. 28, 1976 (2016)] can be extended to simultaneously produce an active, e.g. magnetic, capping layer enabling the realization and control of additional functionalities in such oxide-based 2DESs.
Comment: 5 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/1712.04891Test