Open Access Published by De Gruyter Open Access

Volume 3 Issue 1

January 2017

Issue of Novel Superconducting Materials

Contents
Journal Overview

Open Access February 22, 2017

Metal hydrogen sulfide superconducting temperature

N. A. Kudryashov, A. A. Kutukov, E. A. Mazur

Page range: 1-5

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Abstract

Éliashberg theory is generalized to the electronphonon (EP) systems with the not constant density of electronic states. The phonon contribution to the anomalous electron Green’s function (GF) is considered. The generalized Éliashberg equations with the variable density of electronic states are resolved for the hydrogen sulphide SH 3 phase under pressure. The dependence of both the real and the imaginary part of the order parameter on the frequency in the SH 3 phase is obtained. The T c = 177 K value in the hydrogen sulfide SH 3 phase at the pressure P = 225 GPa has been defined. The results of the solution of the Eliashberg equations for the Im-3m (170 GPa), Im-3m (200 GPa) and R3m (120 GPa) phases are presented. A peak value T c = 241 K of the superconducting transition temperature has been predicted.

Open Access February 22, 2017

Accelerated materials design approaches based on structural classification: application to low enthalpy high pressure phases of SH₃ and SeH₃

José A. Flores-Livas, Antonio Sanna, Stefan Goedecker

Page range: 6-13

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Abstract

We propose a methodology that efficiently asseses major characteristics in the energy landscape for a given space of configurations (crystal structures) under pressure. In this work we study SH 3 and SeH 3 , both of fundamental interest due to their superconducting properties. Starting from the crystal fingerprint, which defines configurational distances between crystalline structures, we introduce an optimal one dimensional metric space that is used to both classify and characterize the structures. Furthermore, this is correlated to the electronic structure. Our analysis highlights the uniqueness of the Im − 3m phase of H 3 S and H3 3 Se for superconductivity. This approach is an useful tool for future material design applications.

Open Access February 22, 2017

Superconductivity in Hydrides Doped with Main Group Elements Under Pressure

Andrew Shamp, Eva Zurek

Page range: 14-22

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Abstract

A priori crystal structure prediction techniques have been used to explore the phase diagrams of hydrides of main group elements under pressure. A number of novel phases with the chemical formulas MHn, n > 1 and M = Li, Na, K, Rb, Cs; MHn, n > 2 and M= Mg, Ca, Sr, Ba; H n I with n > 1 and PH, PH 2 , PH 3 have been predicted to be stable at pressures achievable in diamond anvil cells. The hydrogenic lattices within these phases display a number of structural motifs including H 2 δ− , H − , H − 3 , as well as one-dimensional and three-dimensional extended structures. A wide range of superconducting critical temperatures, T c s, are predicted for these hydrides. The mechanism of metallization and the propensity for superconductivity are dependent upon the structural motifs present in these phases, and in particular on their hydrogenic sublattices. Phases that are thermodynamically unstable, but dynamically stable, are accessible experimentally. The observed trends provide insight on how to design hydrides that are superconducting at high temperatures.

Open Access February 22, 2017

Emergent Magnéli-type crystal phases and their mixture in pressurized sulfur hydride

Ryosuke Akashi, Wataru Sano, Ryotaro Arita, Shinji Tsuneyuki

Page range: 23-28

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Abstract

The pressure-induced superconductivity in sulfur hydride has recently received tremendous amount of interest for its record-breaking transition temperature (T c ) of 203 K. We extensively discuss an infinite sequence of metastable structures of sulfur hydride under high pressure which has been recently proposed theoretically [R. Akashi et al., Phys. Rev. Lett. 117, 075503 (2016)]. The newly found structures are understood as the stacked layers of H2S and H3S, showing close similarity to the Magnéli phases formed in transition-metal oxides. The possible emergence of the “H x S Magnéli” phases are discussed as intermediate metastable phases in the formation of the high-T c H 3 S phase. Superconducting transition temperatures and the Xray diffraction patterns are simulated with the first-principles calculations. It is demonstrated that the H x S Magnéli phases could serve as the silver bullet to explain the complicated dependences of the observed T c s and diffraction patterns on the experimental protocol.

Open Access February 22, 2017

Possible High-Temperature Superconductivity in Hygrogenated Fluorine

D. A. Papaconstantopoulos

Page range: 29-33

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Abstract

Recent computational studies confirmed by experiment have established the occurrence of superconducting temperatures, T c , near 200 K when the pressure is close to 200 GPa in the compound H3S. Motivated by these findings we investigate in this work the possibility of discovering high-temperature superconductivity in the material H 3 F. We performed linearized augmented plane wave(LAPW) calculations followed by the determination of the angular momentum components of the density of states, the scattering phase shifts at the Fermi level and the electron-ion matrix element known as the Hopfield parameter. Our calculated Hopfield parameters are much larger than those found in H 3 S suggesting that they may lead to large electron-phonon coupling constant and hence a large Tc similar or even larger than that of H 3 S. However, calculations of elastic constants are inconclusive regarding the stability of this material.

About this journal

Why subscribe and read

Novel Superconducting Materials [NSM] is the international journal dedicated to the most important advances in the field of novel superconducting materials. NSM features major developments of structural, electronic, magnetic, chemical, thermodynamic, optical properties, and theoretical modeling of new superconducting materials. For readers provides the central and most authoritative publication in the field of novel superconducting materials providing, through the Open Access Model a timely access to its target audience.
Topics include, but are not limited to:

Iron-based Superconductors,
Organic Superconductors,
Carbon-based materials,
Chemical Doping Effects on superconductivity,
New Materials,
Physical and Chemical Properties of New Superconducting Materials,
Material synthesis,
Heterostructures,
Thin Films,
Practical Applications.

Why submit

Novel Superconducting Materials [NSM] is attractive to authors due to its fast and comprehensive peer-review. The central goal of NSM is to serve as a broad spectrum platform for exchanging ideas, and to facilitate collaboration among researchers from all over the world. We are guided by prominent scholars in our Advisory Board, and target high quality submissions from productive and published scholars in the field.

Topical Issues:

High temperature superconductivity in hydrides, Quantum matter in extreme conditions and the roadmap for room temperature superconductivity
Guest Editors:
Antonio Bianconi, Director of the Rome International Center for Materials Science Superstripes RICMASS, Italy
Ryotaro Arita, RIKEN, Japan
Annette Bussmann-Holder, University of Basel, Swiss
Materials and Visions for Superconductivity in the 21st Century
Guest Editor: Silvia Haindl
New superconductors based on BiS_2-layered compounds
Guest Editor: George Martins
Co-editor: Yoshikazu Mizuguchi
Special Issue „Superconductivity in doped p-terphenyl and related organics”
Guest Editors:
Antonio Bianconi, Rome International Center for Materials Science Superstripes RICMASS, Italy
V.P.S. Awana, National Physical Laboratory, New Delhi, India
Pietro Carretta, University of Pavia, Italy

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Volume 3 Issue 1

Issue of Novel Superconducting Materials

Metal hydrogen sulfide superconducting temperature

Abstract

Accelerated materials design approaches based on structural classification: application to low enthalpy high pressure phases of SH3 and SeH3

Abstract

Superconductivity in Hydrides Doped with Main Group Elements Under Pressure

Abstract

Emergent Magnéli-type crystal phases and their mixture in pressurized sulfur hydride

Abstract

Possible High-Temperature Superconductivity in Hygrogenated Fluorine

Abstract

Accelerated materials design approaches based on structural classification: application to low enthalpy high pressure phases of SH₃ and SeH₃