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Condensed Matter, Volume 5, Issue 4

2020 December - 27 articles

Cover Story: Chemical bonding is well adapted to discuss electronic instabilities and their impact on local aspects of superconductivity mechanisms: Mulliken electronegativity, Pearson hardness for atomic polarizability, van der Waals forces for charge-induced dipole interactions. Anionic or cationic clusters may undergo a partial disproportionation, an important phenomenon in chemistry; physicists would refer to this as a « negative-U » system. Is this static description also valid at the pico- and femto-second timescales of phonons and electronic dipole oscillations, respectively? The non-crossing rule imposes the mixing of electron states at the Fermi level, from which partial charge disproportionation occurs. Thus, as shown in this work, two approaches from chemistry lead to coupled charge fluctuations in titanate, cuprate, and iron selenide superconducting systems. View this paper
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Articles (27)

  • Article
  • Open Access
9 Citations
4,755 Views
10 Pages

Structural Phase Diagram of LaO1−xFxBiSSe: Suppression of the Structural Phase Transition by Partial F Substitutions

  • Kazuhisa Hoshi,
  • Shunsuke Sakuragi,
  • Takeshi Yajima,
  • Yosuke Goto,
  • Akira Miura,
  • Chikako Moriyoshi,
  • Yoshihiro Kuroiwa and
  • Yoshikazu Mizuguchi

Recently, the anomalous two-fold-symmetric in-plane anisotropy of superconducting states has been observed in a layered superconductor system, LaO1−xFxBiSSe (x = 0.1 and 0.5), with a tetragonal (four-fold symmetric) in-plane structure. To under...

  • Article
  • Open Access
2 Citations
3,444 Views
7 Pages

It is shown that the translation-invariant bipolaron theory of superconductivity can explain the dependence of the isotope coefficient in high-temperature superconductors on the critical temperature of a superconducting transition: in the case of str...

  • Article
  • Open Access
18 Citations
6,387 Views
22 Pages

Measuring the Electron–Phonon Interaction in Two-Dimensional Superconductors with He-Atom Scattering

  • Giorgio Benedek,
  • Joseph R. Manson,
  • Salvador Miret-Artés,
  • Adrian Ruckhofer,
  • Wolfgang E. Ernst,
  • Anton Tamtögl and
  • Jan Peter Toennies

Helium-atom scattering (HAS) spectroscopy from conducting surfaces has been shown to provide direct information on the electron–phonon interaction, more specifically the mass-enhancement factor λ from the temperature dependence of the De...

  • Perspective
  • Open Access
5 Citations
3,651 Views
4 Pages

A short coherence length is a distinctive feature of many cases of unconventional superconductivity. While in conventional superconductors, it is many orders of magnitude larger than the basic inter-particle distance, a short coherence length is comm...

  • Article
  • Open Access
12 Citations
4,939 Views
13 Pages

Potassium-Doped Para-Terphenyl: Structure, Electrical Transport Properties and Possible Signatures of a Superconducting Transition

  • Nicola Pinto,
  • Corrado Di Nicola,
  • Angela Trapananti,
  • Marco Minicucci,
  • Andrea Di Cicco,
  • Augusto Marcelli,
  • Antonio Bianconi,
  • Fabio Marchetti,
  • Claudio Pettinari and
  • Andrea Perali

Preliminary evidence for the occurrence of high-TC superconductivity in alkali-doped organic materials, such as potassium-doped p-terphenyl (KPT), were recently obtained by magnetic susceptibility measurements and by the opening of a large supercondu...

  • Article
  • Open Access
30 Citations
7,279 Views
9 Pages

Temperature Dependent Structural Evolution of WSe2: A Synchrotron X-ray Diffraction Study

  • Sinu Mathew,
  • Aben Regi Abraham,
  • Sandhya Chintalapati,
  • Soumya Sarkar,
  • Boby Joseph and
  • Thirumalai Venkatesan

A thorough investigation of the structural parameters of micromechanically exfoliated multilayer WSe2 flakes was undertaken between 400 K to 110 K. Crystal structure of WSe2 remains in the trigonal prismatic structure in this temperature range, howev...

  • Review
  • Open Access
67 Citations
22,302 Views
28 Pages

Renewable technologies, and in particular the electric vehicle revolution, have generated tremendous pressure for the improvement of lithium ion battery performance. To meet the increasingly high market demand, challenges include improving the energy...

  • Article
  • Open Access
2 Citations
5,021 Views
12 Pages

Internal energies, enthalpies, phonon dispersion curves, and superconductivity of atomic metallic hydrogen are calculated. The standard use of pseudopotentials in density-functional theory are compared with full Coulomb-potential, all-electron linear...

  • Article
  • Open Access
13 Citations
4,088 Views
11 Pages

On the Elastic Properties and Fracture Patterns of MoX2 (X = S, Se, Te) Membranes: A Reactive Molecular Dynamics Study

  • Marcelo Lopes Pereira Júnior,
  • Cícera Maria Viana de Araújo,
  • José Moreira De Sousa,
  • Rafael Timóteo de Sousa Júnior,
  • Luiz Fernando Roncaratti Júnior,
  • William Ferreira Giozza and
  • Luiz Antonio Ribeiro Júnior

We carried out fully-atomistic reactive molecular dynamics simulations to study the elastic properties and fracture patterns of transition metal dichalcogenide (TMD) MoX2 (X = S, Se, Te) membranes, in their 2H and 1T phases, within the framework of t...

  • Article
  • Open Access
5 Citations
4,558 Views
14 Pages

Detection of Spin Polarized Band in VO2/TiO2(001) Strained Films via Orbital Selective Constant Initial State Spectroscopy

  • Alessandro D’Elia,
  • Cesare Grazioli,
  • Albano Cossaro,
  • Bowen Li,
  • Chongwen Zou,
  • Seyed Javad Rezvani,
  • Augusto Marcelli and
  • Marcello Coreno

The VO2 is a 3d1 electron system that undergoes a reversible metal–insulator transition (MIT) triggered by temperature and characterized by an interplay between orbital, charge and lattice degrees of freedom. The characterization of the MIT fea...

  • Feature Paper
  • Article
  • Open Access
5 Citations
4,805 Views
10 Pages

Asymmetric Hysteresis Loops in Co Thin Films

  • Andrea Ehrmann and
  • Tomasz Blachowicz

Asymmetric magnetic hysteresis loops are usually found in exchange bias (EB) systems, typically after field cooling a system below the Néel temperature of an antiferromagnet exchange coupled to a ferromagnet. Alternatively, asymmetric hysteres...

  • Article
  • Open Access
40 Citations
6,165 Views
27 Pages

In a semi-review paper, we show that the local pseudo-Jahn–Teller effect (PJTE) in transition metal B ion center of ABO3 perovskite crystals, notably BaTiO3, is the basis of all their main properties. The vibronic coupling between the ground an...

  • Feature Paper
  • Article
  • Open Access
4 Citations
4,594 Views
12 Pages

First-Principles Calculation of Copper Oxide Superconductors That Supports the Kamimura-Suwa Model

  • Hiroshi Kamimura,
  • Masaaki Araidai,
  • Kunio Ishida,
  • Shunichi Matsuno,
  • Hideaki Sakata,
  • Kenji Shiraishi,
  • Osamu Sugino and
  • Jaw-Shen Tsai

In 1986 Bednorz and Műller discovered high temperature superconductivity in copper oxides by chemically doping holes into La2CuO4 (LCO), the antiferromagnetic insulator. Despite intense experimental and theoretical research during the past 34 years,...

  • Review
  • Open Access
7 Citations
5,595 Views
16 Pages

I present here a short memory of my scientific contacts with K.A. Müller starting from the Interlaken Conference (1988), Erice (1992 and 1993), and Cottbus (1994) on the initial studies on phase separation (PS) and charge inhomogeneity in cuprat...

  • Article
  • Open Access
4 Citations
3,342 Views
29 Pages

Are Superconductivity Mechanisms a Matter for Chemists?

  • Michel Pouchard and
  • Antoine Villesuzanne

From a tight-binding approach to the instability of nonbonding electronic states, along a double-well potential, we consider here how the coupling of these states with a phonon mode can open a superconducting gap at the Fermi level. The alternation o...

  • Feature Paper
  • Article
  • Open Access
12 Citations
4,484 Views
19 Pages

Temperature-Independent Cuprate Pseudogap from Planar Oxygen NMR

  • Jakob Nachtigal,
  • Marija Avramovska,
  • Andreas Erb,
  • Danica Pavićević,
  • Robin Guehne and
  • Jürgen Haase

Planar oxygen nuclear magnetic resonance (NMR) relaxation and shift data from all cuprate superconductors available in the literature are analyzed. They reveal a temperature-independent pseudogap at the Fermi surface, which increases with decreasing...

  • Feature Paper
  • Article
  • Open Access
1 Citations
3,721 Views
23 Pages

Phase Separation and Pairing Fluctuations in Oxide Materials

  • Andreas Bill,
  • Vladimir Hizhnyakov,
  • Reinhard K. Kremer,
  • Götz Seibold,
  • Aleksander Shelkan and
  • Alexei Sherman

The microscopic mechanism of charge instabilities and the formation of inhomogeneous states in systems with strong electron correlations is investigated. We demonstrate that within a strong coupling expansion the single-band Hubbard model shows an in...

  • Article
  • Open Access
2 Citations
3,054 Views
19 Pages

We formulate the statistics of the discrete multicomponent fragmentation event using a methodology borrowed from statistical mechanics. We generate the ensemble of all feasible distributions that can be formed when a single integer multicomponent mas...

  • Article
  • Open Access
6 Citations
4,284 Views
9 Pages

Unconventional Transport Properties of Reduced Tungsten Oxide WO2.9

  • Alexander Shengelaya,
  • Fabio La Mattina and
  • Kazimierz Conder

The temperature and magnetic field dependence of resistivity in WO2.9 was investigated. The variation of resistivity with temperature displayed unusual features, such as a broad maximum around 230 K and a logarithmic increase of resistivity below 16...

  • Creative
  • Open Access
3,042 Views
9 Pages

This contribution presents a personal account of the influence Karl Alex Müller had on the early stages of my career and the scientific questions about which we exchanged our views over the years. While both our research branched into a variety...

  • Article
  • Open Access
18 Citations
8,710 Views
10 Pages

Ferroelectricity, Superconductivity, and SrTiO3—Passions of K.A. Müller

  • Gernot Scheerer,
  • Margherita Boselli,
  • Dorota Pulmannova,
  • Carl Willem Rischau,
  • Adrien Waelchli,
  • Stefano Gariglio,
  • Enrico Giannini,
  • Dirk van der Marel and
  • Jean-Marc Triscone

SrTiO3 is an insulating material which, using chemical doping, pressure, strain or isotope substitution, can be turned into a ferroelectric material or into a superconductor. The material itself, and the two aforementioned phenomena, have been subjec...

  • Article
  • Open Access
4,209 Views
33 Pages

Here, classical and quantum field theory of dipolar, axisymmetric quadrupolar and octupolar Bose gases is considered within a general approach. Dipole, axisymmetric quadrupole and octupole interaction potentials in the momentum representation are cal...

  • Article
  • Open Access
11 Citations
4,013 Views
11 Pages

Interfacial Crystallization within Liquid Marbles

  • Edward Bormashenko,
  • Pritam Kumar Roy,
  • Shraga Shoval and
  • Irina Legchenkova

We report interfacial crystallization in the droplets of saline solutions placed on superhydrophobic surfaces and liquid marbles filled with the saline. Evaporation of saline droplets deposited on superhydrophobic surface resulted in the formation of...

  • Review
  • Open Access
14 Citations
4,455 Views
12 Pages

SrTiO3—Glimpses of an Inexhaustible Source of Novel Solid State Phenomena

  • Wolfgang Kleemann,
  • Jan Dec,
  • Alexander Tkach and
  • Paula M. Vilarinho

The purpose of this selective review is primarily to demonstrate the large versatility of the insulating quantum paraelectric perovskite SrTiO3 explained in “Introduction” part, and “Routes of SrTiO3 toward ferroelectricity and othe...

  • Article
  • Open Access
3 Citations
3,743 Views
11 Pages

Engineering Porous Silicon Nanowires with Tuneable Electronic Properties

  • S. Javad Rezvani,
  • Nicola Pinto,
  • Roberto Gunnella,
  • Alessandro D’Elia,
  • Augusto Marcelli and
  • Andrea Di Cicco

Structural and electronic properties of silicon nanowires with pre-designed structures are investigated. Wires with distinct structure were investigated via advanced spectroscopic techniques such as X-ray absorption spectroscopy and Raman scattering...

  • Communication
  • Open Access
1 Citations
2,788 Views
11 Pages

Both phenomena mentioned in the title were revealed by the electron paramagnetic resonance (EPR) method. The first phenomenon was found in superconducting La metal with Er impurities—the spin relaxation rate of the erbium impurities was sharply...

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Condens. Matter - ISSN 2410-3896