Related papers: Finite-wavevector Jahn-Teller-pairing and supercon…
A brief history of the discovery of new superconductors is given. Different types of pairing mechanisms are considered. By comparing Tcs in different cuprate families it is concluded that the pairing in the CuO2 layers must be supplemented…
The electronic properties of many transition metal oxide systems require new ideas concerning the behaviour of electrons in solids for their explanation. A recent example, subsequent to that of cuprate superconductors, is of rare earth…
In conventional metal superconductors such as aluminum, the large number of weakly bounded Cooper pairs become phase coherent as soon as they start to form. The cuprate high critical temperature ($T_c$) superconductors, in contrast, belong…
The phenomena of superconductivity and charge density waves are observed in close vicinity in many strongly correlated materials. Increasing evidence from experiments and numerical simulations suggests both phenomena can also occur in an…
We consider a renormalization group study of the problem of coupled stripes of holes in cuprates. We use a model of a mesh of horizontal and vertical stripes and study the problemof superconductivity via the Josephson coupling. We discuss…
Using high resolution angle-resolved photoemission data in conjunction with that from neutron and other probes, we show that electron-phonon (el-ph) coupling is strong in cuprates superconductors and it plays an important role in pairing.…
In 1937 the Jahn-Teller (JT) effect addressed the instability (potential or actual) of non-linear symmetric molecules with degenerate orbital electronic states. In view of the large variety of JT activity that has taken place since then, we…
The properties of a dilute electron gas, coupled to the lattice degrees of freedom, are studied and compared with the properties of an electron gas at half-filling, where spinless fermions with two orbitals per lattice site are considered.…
The relevance of magnetism for the mechanism responsible for high-temperature superconductivity remains an open and still interesting issue. The observation by inelastic neutron scattering of strong antiferromagnetic dynamical correlations…
We have analyzed different correlation functions in a realistic spin-orbital model for half-doped manganites. Using a finite-temperature diagonalization technique the CE phase was found in the charge-ordered phase in the case of small…
The trivalent alkali fullerides A$_3$C$_{60}$, where C$_{60}$ are a well established family of molecular superconductors. The electron pairing has s-wave symmetry and is due to standard electron-phonon coupling, in particular by Jahn-Teller…
Central issues in the electronic structure of underdoped cuprate superconductors are to clarify the shape of the Fermi surfaces and the origin of a pseudogap. Based on the model proposed by Kamimura and Suwa which bears important…
The phase diagram of half-doped manganite systems of formula A_{0.5}A'_{0.5}MnO_3 is investigated within a single-orbital model incorporating magnetic double-exchange and superexchange, together with intersite Coulomb and electron-lattice…
The properties of transition metal compounds are largely determined by nontrivial interplay of different degrees of freedom: charge, spin, lattice, but also orbital ones. Especially rich and interesting effects occur in systems with orbital…
In quantum dot circuits, screening electron clouds in strongly-coupled leads will hybridize with the states of the artificial atom. Using a three-terminal geometry, we directly probe the atomic structure of a quantum dot with Kondo…
The appearance of spontaneous polarization in CuInP$_{2}$S$_{6}$ ferrielectrics is related to the second order Jahn-Teller effect for copper cations located in a double-well local potential, the stereoactivity of indium cations located in a…
A simple interlayer pair tunneling is solved exactly. We find that in the normal state spin-1/2 particle and hole excitations are gapped. But the state is an unusual metal, characterized by novel fermionic spin zero and charge +2e and -2e…
There is increasing experimental evidence that the superconducting energy gap $\Delta_0$ in the underdoped cuprates is independent of doping concentration $x$ while the superfluid density is linear in $x$. We show that under these…
The formation of Cooper pairs, a bound state of two electrons of opposite spin and momenta by exchange of a phonon [1], is a defining feature of conventional superconductivity. In the cuprate high temperature superconductors, even though it…
Despite intense efforts during the last 25 years, the physics of unconventional superconductors, including the cuprates with a very high transition temperature, is still a controversial subject. It is believed that superconductivity in many…