Magnetism and superconductivity compete or interact in complex and intricate ways. Here we review the special case where novel magnetic phenomena appear due to superconductivity, but do not exist without it. Such states have recently been identified in unconventional superconductors. They are different from the mere coexistence of magnetic order and superconductivity in conventional superconduc...

We use Ni and Zn impurities doped into Bi2Sr2CaCu2O8+x (Bi2212) to test the MS (Magnetic polaron Spinon) model proposed earlier. We present electron-tunneling spectroscopy of pure, Niand Zn-doped Bi2212 single crystals below Tc using a break-junction technique. We show that magnetic (Ni) and nonmagnetic (Zn) impurities doped into CuO2 planes affect both the Tc and the density of states in Bi221...

The parent compound of the copper-oxide high-temperature superconductors is a Mott insulator. Superconductivity is realized by doping an appropriate amount of charge carriers. How a Mott insulator transforms into a superconductor is crucial in understanding the unusual physical properties of high-temperature superconductors and the superconductivity mechanism. Here we report high-resolution ang...

Superconductivity, which is a quantum state induced by spontaneous gauge symmetry breaking, frequently emerges in low-dimensional materials. Hence, low dimensionality has long been considered as necessary to achieve high superconducting transition temperatures (TC). The recently discovered post-perovskite (ppv) MgSiO3, which constitutes the Earth's lowermost mantle (D" layer), has attracted sig...

Pressure can tune material's electronic properties and control its quantum state, making some systems present disconnected superconducting region as observed in iron chalcogenides and heavy fermion CeCu2Si2. For CaC6 superconductor (Tc of 11.5 K), applying pressure first Tc increases and then suppresses and the superconductivity of this compound is eventually disappeared at about 18 GPa. Here, ...

Functionalities of two-dimensional (2D) crystals based on semiconducting transition metal dichalcogenides (TMDs) have now stemmed from simple field effect transistors (FETs) to a variety of electronic and opto-valleytronic devices, and even to superconductivity. Among them, superconductivity is the least studied property in TMDs due to methodological difficulty accessing it in different TMD spe...

The fundamental degrees of freedom of QCD, i.e., quarks and gluons, have never been observed in experiments. Only the color singlet combinations, hadrons (mesons and baryons) and glueballs, are expected to be observed. We wish to answer the question why color confinement occurs. In particular, we wish to clarify what the mechanism for quark confinement is. Dual superconductivity picture propose...

Enhanced superconductivity is sought by employing heterostructures composed of boron-doped graphene and iron selenide. Build-up of a composite manifold of near-degenerate noninteracting states formed by coupling top-of-valence-band states of FeSe to bottom-of-conductionband states of boron-doped graphene is demonstrated. Intraand intersubsystem excitons are explored by means of density function...