Related papers: Spin dynamics in high-$T_C$ superconductors
We briefly review a theory for the cuprates that has been recently proposed based on the movement and interaction of holes in antiferromagnetic (AF) backgrounds. A robust peak in the hole density of states (DOS) is crucial to produce a…
We present the results of numerical studies of superconductivity and antiferromagnetism in a strongly correlated electron system. To do this we construct a Hubbard model on a lattice of self-consistently embedded multi-site clusters by…
We consider the condensation energy, $E_c$ of strongly coupled, magnetically-mediated superconductors within the context of the spin fermion model. We argue that although experimentally obtained values of $E_c$ are of the same order of…
We followed step by step the transition from an antiferromagnetic (AF) Mott insulator to a superconducting (SC) metal in the Bi$_2$Sr$_2$CaCu$_{2}$O$_{8+\delta}$ (Bi-2212) cuprate using the electronic Raman scattering spectroscopy. This was…
The 2008 discovery of superconducting ferropnictides with Tc~26K-56K introduced a new family of materials into the category of high Tc superconductors. The ongoing project of understanding the superconducting mechanism and pairing symmetry…
The physical properties of low energy superconducting quasiparticles in high- $T_c$ superconductors are examined using magnetic penetration depth and specific heat experimental data. We find that the low energy density of states of…
We review the search for a mediator of high-Tc superconductivity focusing on ARPES experiment. In case of HTSC cuprates, we summarize and discuss a consistent view of electronic interactions that provides natural explanation of both the…
Recently it was revealed that the whole Fermi surface is fully gapped for several families of underdoped cuprates. The existence of the finite energy gap along the $d$-wave nodal lines ("nodal gap") contrasts the common understanding of the…
We analyze antiferromagnetism and superconductivity in novel $Fe-$based superconductors within the itinerant model of small electron and hole pockets near $(0,0)$ and $(\pi,\pi)$. We argue that the effective interactions in both channels…
The underdoped cuprates have a number of interesting and unusual properties that often seem hard to reconcile with one another. In this paper we show how many of these diverse phenomena can be synthesized into a single coherent theoretical…
The evidence for the spin density wave (SDW) nature of the pseudogap in HTSC cuprates is presented from resistive and direct gap measurements (ARPES, tunneling experiments, etc.). Its d-wave symmetry mimics the symmetry of the order…
General theory of d-wave quasiparticles coupled to phase fluctuations of superconducting order parameter is discussed. In the charge sector the superfluid density is found to conform to Uemura scaling, and the charge renormalization factor…
Although it is generally accepted that superconductivity (SC) is unconventional in the high- transition temperature copper oxides (high-Tc cuprates), the relative importance of phenomena such as spin and charge (stripe) order, SC…
The issue of the mechanism of high-Tc superconductivity remains open. In this contribution, we propose a new scenario for the mechanism of superconductivity in cuprates based on analysis of experimental data, mainly tunneling, neutron…
The density-of-states at the Fermi energy, $N(E_F)$, is low in doped superconducting semiconductors and high-$T_C$ cuprates. This contrasts with the common view that superconductivity requires a large electron-boson coupling $\lambda$ and…
Within the t-J model of copper-oxides, the condensation energy can be related to the change in the dynamical spin structure factor between the superconducting and the normal states. By analyzing previous experimental data, we show that the…
We theoretically study potential unconventional superconductivity in doped AB-type IV-VI semi-conductors, based on a minimal effective model with interaction up to the next-nearest neighbors. According to the experimental implications, we…
We propose a model for high-Tc superconductors that includes both the spin fluctuations of the Cu++ magnetic ions and of the spins of O-- doped holes (spinons). The charge of the dopants (holons) is associated to quantum skyrmion…
We investigate the magnetic and superconducting properties in electron-doped Li$_x$HfNCl. HfNCl is a band insulator that undergoes an insulator to superconductor transition upon doping at $x\approx0.13$. The persistence of the insulating…
We present a phenomenological model for the vortex dynamics in the peak effect region of weakly pinned superconductors. We explain the history dependent dynamic response of the metastable vortex states subjected to a transport current and…