scholarly journals Discrete symmetries of low-dimensional Dirac models: a selective review with a focus on condensed-matter realizations

2015 ◽  
Vol 57 ◽  
pp. 3
Author(s):  
Roland Winkler ◽  
Ulrich Zuelicke
Keyword(s):  
Discrete Symmetries ◽  
Condensed Matter ◽  
Selective Review ◽  
Low Dimensional

Bereziskii-Kosterlitz-Thouless transition in the Weyl system PtBi2

2021 ◽  
Author(s):  
Arthur Veyrat ◽  
Valentin Labracherie ◽  
Rohith Acharya ◽  
Dima Bashlakov ◽  
Federico Caglieris ◽  
...  
Keyword(s):  
Condensed Matter ◽  
Three Dimensional ◽  
Spin Orbit Coupling ◽  
Two Dimensional ◽  
Pairing Mechanism ◽  
Critical Fields ◽  
Weyl Semimetal ◽  
Superconducting Coherence Length ◽  
Low Dimensional ◽  
Strong Spin

Abstract Symmetry breaking in topological matter became, in the last decade, a key concept in condensed matter physics to unveil novel electronic states. In this work, we reveal that broken inversion symmetry and strong spin-orbit coupling in trigonal PtBi2 lead to a Weyl semimetal band structure, with unusually robust two-dimensional superconductivity in thin fims. Transport measurements show that high-quality PtBi2 crystals are three-dimensional superconductors (Tc≈600 mK) with an isotropic critical field (Bc≈50 mT). Remarkably, we evidence in a rather thick flake (60 nm), exfoliated from a macroscopic crystal, the two-dimensional nature of the superconducting state, with a critical temperature Tc≈370 mK and highly-anisotropic critical fields. Our results reveal a Berezinskii-Kosterlitz-Thouless transition with TBKT≈310 mK and with a broadening of Tc due to inhomogenities in the sample. Due to the very long superconducting coherence length ξ in PtBi2, the vortex-antivortex pairing mechanism can be studied in unusually-thick samples (at least five times thicker than for any other two-dimensional superconductor), making PtBi2 an ideal platform to study low dimensional superconductivity in a topological semimetal.

ONE AND QUASI-ONE DIMENSIONAL SPIN SYSTEMS

2003 ◽  
Vol 18 (33n35) ◽  
pp. 2329-2336 ◽  
Author(s):  
Elisa Ercolessi
Keyword(s):  
Condensed Matter ◽  
Quantum Spin ◽  
Spin Systems ◽  
Spin Chains ◽  
Famous Conjecture ◽  
One Dimensional ◽  
Conformal Field ◽  
Quantum Spin Models ◽  
Low Dimensional ◽  
Antiferromagnetic Spin

Quantum spin models represent one of the most studied examples of application of low-dimensional field theories to condensed matter systems. In this paper we will review some chapters of this hystory, that dates back to the early '80, when Haldane put forward his by now famous conjecture on antiferromagnetic spin chains, and reaches the present days, with the most advanced applications of integrable models and conformal field theory.

scholarly journals Magnetic oxygen stored in quasi-1D form within BaAl2O4 lattice

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Martina Vrankić ◽  
Ankica Šarić ◽  
Sanja Bosnar ◽  
Damir Pajić ◽  
Jure Dragović ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Condensed Matter ◽  
Magnetic Ordering ◽  
Inorganic Materials ◽  
Dimensional Chain ◽  
Ambient Conditions ◽  
Gas Atmosphere ◽  
Fertile Ground ◽  
Reduce Energy Consumption ◽  
Low Dimensional

Abstract Inorganic materials that enable a link between the storage and release of molecular oxygen offer a fertile ground in continuous quest for the applications that can potentially reduce energy consumption and thus minimize adverse effects on the environment. Herein, we address reversible intake/release of an oxygen within the BaAl2O4 material as evidenced by unexpected magnetic ordering. Magnetic measurements unveil that an oxygen is stored in the form of condensed matter, creating a kind of low dimensional, chain-like assembly within the tunnels of BaAl2O4 structure. We demonstrate that oxygen is adsorbed simply by staying in air, at ambient conditions, and released relatively quickly by staying in the He or other gas atmosphere of several millibars pressure even at 300 K.

scholarly journals Optimization of moderators and beam extraction at the ESS

2018 ◽  
Vol 51 (2) ◽  
pp. 264-281 ◽  
Author(s):  
Ken Holst Andersen ◽  
Mads Bertelsen ◽  
Luca Zanini ◽  
Esben Bryndt Klinkby ◽  
Troels Schönfeldt ◽  
...  
Keyword(s):  
Neutron Source ◽  
Free Choice ◽  
Cold Neutron ◽  
Condensed Matter ◽  
Beam Extraction ◽  
High Brightness ◽  
Cold Neutron Source ◽  
Technical Design Report ◽  
Spallation Source ◽  
Low Dimensional

A global approach coupling the moderator to the beam extraction system has been applied for the design optimization of the thermal and cold moderators of the European Spallation Source (ESS), which will be the brightest neutron source in the world for condensed-matter studies. The design is based on the recently developed high-brightness low-dimensional moderator concepts.Para-hydrogen is used for the cold neutron source, while thermal neutrons are provided by moderation in water. The overall moderation configuration was chosen in order to satisfy a range of requirements on bispectral extraction, beamport configuration and instrument performance. All instruments are served by a single moderator assembly above the target, arranged in a `butterfly' geometry with a height of 3 cm. This was determined to be the optimal height for trade-off between high brightness and efficient guide illumination, by analysis of the performance of 23 instruments, based on the reference suite of the ESS Technical Design Report. The concept of `brilliance transfer' is introduced to quantify the performance of the neutron optical system from the source to the sample. The target monolith incorporates a grid of 42 neutron beamports with an average separation of 6°, allowing a free choice between cold and thermal neutron sources at all instrument positions. With the large number of beamports and the space below the target available for future moderators, ample opportunities are available for future upgrades.

scholarly journals Nanoscience and Nanotechnology, Proceedings of the INFN-LNF 2018 Conference

2019 ◽  
Vol 4 (4) ◽  
pp. 88
Author(s):  
Stefano Bellucci
Keyword(s):  
Condensed Matter ◽  
Energy Materials ◽  
Nanoscience And Nanotechnology ◽  
Refereeing Process ◽  
Recent Developments ◽  
Low Dimensional ◽  
Year 2000

The NEXT Nanotechnology group at INFN-Laboratori Nazionali di Frascati (LNF) has organized, since the year 2000, a yearly series of international meetings in the area of nanotechnology. The 2018 conference has been devoted to recent developments in nanoscience and their manifold technological applications. These consisted of a number of tutorial/keynote lectures, as well as research talks presenting frontier nanoscience research developments and innovative nanotechnologies in the areas of biology, medicine, aerospace, optoelectronics, energy, materials and characterizations, low-dimensional nanostructures and devices. Selected, original papers based on the 2018 conference talks and related discussions have been published, after a careful refereeing process, in the MDPI journal Condensed Matter, and are currently included in the present dedicated issue.

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