Phase transitions metal-superconductor

This work shows the exceptional physics that can be done with a STM operated at cryogenic temperatures and the availability of STMs working down to liquid helium temperature opens broad avenues of research in the coming years. No doubt that among the many future scientific experiments accessible with low temperature STMs, the real-space electronic characterization of the metal-superconductor transition in /c-phases of BEDT-TTF salts, because Tc > 4 K, as well as the study of magnetic ordering in MOMs, will certainly occupy a relevant position. 

Keywords Charge transfer solid Electronic dimensionality Functional organic solid Ionicity diagram Organic metal Organic superconductor Phase transition Quantum spin liquid state Switching... 

It has now become apparent that f-band superconductors can be understood in a normal way, like d-band ones" we have just to think about density of states, bandwidth lattice unstabilities and electron correlations to interpret it. This was clearly summarized by Smith after the discovery of superconductivity of Pa and Am. Superconductivity of Am is made by the J = 0 ground state of its six 5 f electrons as was stressed by Johansson , this could also be the case for stabilized trivalent europium metal. The importance of lattice instabilities (like in A-15 high Tc superconductors) was put forward by Fournier who showed that the very large 6T/8p slope for U was mainly due to a very targe change in the electron-phonon coupling associated with the low temperature phase transition. 

BEDT-TTF)2X and Other Organic Superconductors. Cava13 and co-workers synthesized the "all-sulfur" donor BEDT-TTF (bis-ethylenedithiolene-tetrathiafulvalene, or ET for short, 17a) [31]. Saito14 and co-workers found that in some (ET)2X salts the metal-to-insulator phase transition was... 

With the discovery of superconductivity (Tc = 15.5 K) in the Y-Ni-B-C system [6, 80], a new class of quaternary borocarbide superconductors has emerged. Superconductivity has been observed in several rare earth (Lu, Tm, Er and Ho) nickel borocarbides[80], and with transition metals such as Pd and Pt. The superconducting phase having the composition of YNi2B2C, crystallizes [81] in a tetragonal structure with alternating Y-C and Ni2B2 layers. Band structure calculations [82] indicate that these materials, unlike cuprate superconductors, are three-dimensional metals. 

The problematic nature of the melting transition can be illustrated by comparison with other well-known first-order phase transitions, for instance the normal metal-(low T ) superconductor transition. The normal metal-superconductor and melting transitions have similar symptomatic definitions, the former being a loss of resistance to current flow, and the latter being a loss of resistance to shear. However, superconductivity can also be neatly described as a phonon-mediated (Cooper) pairing of electrons and condensation of Cooper pairs into a coherent ground state wave function. This mechanistic description of the normal metal-super-conductor transition has required considerable theoretical effort for its development, but nevertheless boils down to a simple statement, indicat-... 

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