Alkali-doped Fullerides
Alkali-doped Fullerides

Author: Olle Gunnarsson

Publisher: World Scientific

Published: 2004

Total Pages: 301

ISBN-13: 981238667X

DOWNLOAD EBOOK

Alkali-doped fullerides have attracted strong interest since their production became possible about fifteen years ago. This book presents recent work which may solve intriguing problems arising from a variety of remarkable properties. For example, these solids are superconductors with high transition temperatures, although the similarity between the electronic and phonon energy scales should suppress superconductivity. Moreover, the Ioffe-Regel condition for electrical conductivity is strongly violated. The book shows why superconductivity is nevertheless possible, owing to a local pairing mechanism. The Ioffe-Regel condition is derived quantum-mechanically, and it is explained why the underlying assumptions are violated for fullerides and high-c cuprates, for example. The book treats electronic and transport properties, reviewing theoretical and experimental results. It focuses on superconductivity, electrical conductivity and metal-insulator transitions, emphasizing the electron-electron and electron-phonon interactions as well as the Jahn-Teller effect.

Alkali-doped Fullerides
Alkali-doped Fullerides

Author: Olle Gunnarsson

Publisher: World Scientific

Published: 2004

Total Pages: 301

ISBN-13: 9812794956

DOWNLOAD EBOOK

Alkali-doped fullerides have attracted strong interest since their production became possible about fifteen years ago. This book presents recent work which may solve intriguing problems arising from a variety of remarkable properties. For example, these solids are superconductors with high transition temperatures, although the similarity between the electronic and phonon energy scales should suppress superconductivity. Moreover, the IoffeOCoRegel condition for electrical conductivity is strongly violated. The book shows why superconductivity is nevertheless possible, owing to a local pairing mechanism. The IoffeOCoRegel condition is derived quantum-mechanically, and it is explained why the underlying assumptions are violated for fullerides and high- T c cuprates, for example. The book treats electronic and transport properties, reviewing theoretical and experimental results. It focuses on superconductivity, electrical conductivity and metalOCoinsulator transitions, emphasizing the electronOCoelectron and electronOCophonon interactions as well as the JahnOCoTeller effect. Contents: Structural Properties; Models and Parameters; Phonons and ElectronOCoPhonon Coupling Strength; Interacting ElectronOCoPhonon System; Electronic Structure; Plasmons; MetalOCoInsulator Transition; Electrical Resistivity; Superconductivity. Readership: Graduate students and researchers in condensed matter physics."

Ab Initio Studies on Superconductivity in Alkali-Doped Fullerides
Ab Initio Studies on Superconductivity in Alkali-Doped Fullerides

Author: Yusuke Nomura

Publisher: Springer

Published: 2016-08-03

Total Pages: 158

ISBN-13: 9811014426

DOWNLOAD EBOOK

This book covers high-transition temperature (Tc) s-wave superconductivity and the neighboring Mott insulating phase in alkali-doped fullerides. The author presents (1) a unified theoretical description of the phase diagram and (2) a nonempirical calculation of Tc. For these purposes, the author employs an extension of the DFT+DMFT (density-functional theory + dynamical mean-field theory). He constructs a realistic electron–phonon-coupled Hamiltonian with a newly formulated downfolding method. The Hamiltonian is analyzed by means of the extended DMFT. A notable aspect of the approach is that it requires only the crystal structure as a priori knowledge. Remarkably, the nonempirical calculation achieves for the first time a quantitative reproduction of the experimental phase diagram including the superconductivity and the Mott phase. The calculated Tc agrees well with the experimental data, with the difference within 10 K. The book provides details of the computational scheme, which can also be applied to other superconductors and other phonon-related topics. The author clearly describes a superconducting mechanism where the Coulomb and electron–phonon interactions show an unusual cooperation in the superconductivity thanks to the Jahn–Teller nature of the phonons.

First-Principles Computational Studies of Alkali-Doped C60 Fullerides
First-Principles Computational Studies of Alkali-Doped C60 Fullerides

Author:

Publisher:

Published: 1992

Total Pages: 10

ISBN-13:

DOWNLOAD EBOOK

Researchers at AT and T Bell Laboratories reported the discovery of superconductivity at 18 K in a potassium-doped fullerene solid, KxC60. This marked a major turning point in the young history of the C60 molecule 'buckminsterfullerene: from a hypothetical molecular (1085), to small-scale (mg) production of crystalline powders (1988), to large-scale synthesis (1990), to a material with the highest transition temperature of any molecular superconductor. This history represents only one of many research lines. Concurrently with the work at AT and T on partial doping, researchers at the Laboratory for Research on the Structure of Matter at the University of Pennsylvania were doping solid C60 to saturation with potassium. The resulting pure phase, K6C60, was characterized by x-ray diffraction in April 1991: the lattice was body-centered cubic, with the C60 molecules essentially undistorted, orientationally ordered, and each surrounded by a cage of 24 K atoms. Nothing was known about the electronic structure at this early stage.

The Fullerenes
The Fullerenes

Author: H.W. Kroto

Publisher: Newnes

Published: 2012-12-02

Total Pages: 327

ISBN-13: 008098472X

DOWNLOAD EBOOK

Until recently, the element carbon was believed to exhibit only two main allotropic forms, diamond and graphite. Research in the US and Europe has now confirmed the existence of a third previously unknown form - buckminsterfullerene (C60) and its relatives, the fullerenes (C24, C28, C32, C70 etc). The story of fullerene chemistry, physics and materials science began in 1985, almost twenty years after the existence of a spherical carbon cluster was first considered. In September 1985 a joint Sussex/Rice Universities team including Kroto, Heath, O'Brien, Curl and Smalley used a powerful mass spectrometric technique to identify the C+60 species, and proposed a spherical structure and the name buckminsterfullerene. It was not, however, until Krätschmer and Huffman reported the isolation of crystals of C60 in 1990 that the closed cage structure of C60 could be confirmed. The Fullerenes documents the work leading up to 1990 and more recent developments in the field of fullerene research and will serve as an indispensible reference tool for all workers in this area.

Room-temperature Superconductivity
Room-temperature Superconductivity

Author: Andrei Mourachkine

Publisher: Cambridge Int Science Publishing

Published: 2004

Total Pages: 326

ISBN-13: 1904602274

DOWNLOAD EBOOK

Annotation The first book dealing with the subject of room-temperature conductivity.