Related papers: Hg-Based Superconducting Cuprates: High Tc and Pse…
$^{63}$Cu and $^{199}$Hg NMR shifts for an optimally and underdoped HgBa$_{2}$CuO$_{4+\delta}$ single crystal are reported, and the temperature dependence dictates a two-component description of the uniform spin susceptibility. The first…
A quantum critical point in the single layer, hole-doped cuprate system La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ (Nd-LSCO), near $x$ = 0.23 has been proposed as an organizing principle for understanding high temperature superconductivity. Our…
Spin fluctuations (SF) and SF-mediated superconductivity (SC) in quasi-two-dimensional metals around the antiferrromagnetic (AF) quantum critical point (QCP) are investigated by using the self-consistent renormalization theory for SF and…
Unveiling the nature of the pseudogap and its relation to both superconductivity and antiferromagnetic Mott insulators, the pairing mechanism, and a non-Fermi liquid phase is a key issue for understanding high temperature superconductivity…
Pressure-induced superconductivity in a spin-ladder cuprate Sr$_2$Ca$_{12}$Cu$_{24}$O$_{41}$ has not been studied on a microscopic level so far although the superconductivity was already discovered in 1996. We have improved high-pressure…
In order to fully utilize the technological potential of unconventional superconductors, an enhanced understanding of the superconducting mechanism is necessary. In the best performing superconductors, the cuprates, superconductivity is…
We report a coexistence of superconductivity and antiferromagnetism in five-layered compound HgBa$_2$Ca$_4$Cu$_5$O$_y$ (Hg-1245) with $T_c=108$ K, which is composed of two types of CuO$_2$ planes in a unit cell; three inner planes (IP's)…
The relation between pseudogap (PG) and superconducting (SC) gap, whether PG is a precursor of SC or they coexist or compete, is a long-standing controversy in cuprate high-temperature supercondutors. Here, we report ultrafast time-resolved…
The nature of the pseudogap in high transition temperature (high-Tc) superconducting cuprates has been a major issue in condensed matter physics. It is still unclear whether the high-Tc superconductivity can be universally associated with…
We derive analytic expressions for the critical temperatures of the superconducting (SC) and pseudogap (PG) phases of the high-Tc cuprates, which are in excellent agreement with the experimental data for single-layered materials such as…
We analyze pseudogap phenomena widely observed in the underdoped cuprates. We assume the existence of a strong d-wave pairing force competing with antiferromagnetic(AFM) fluctuations and the formation of flat and damped dispersion around…
Establishing the presence and the nature of a quantum critical point in their phase diagram is a central enigma of the high-temperature superconducting cuprates. It could explain their pseudogap and strange metal phases, and ultimately…
The pseudogap state is one of the peculiarities of the cuprate high temperature superconductors. Here we investigate its presence in BaCo$_{x}$Fe$_{2-x}$As$_{2}$, a member of the pnictide family, with temperature dependent scanning…
We investigate the spectral properties of the doped ${t-t'}$ Hubbard model with parameters typical for high-temperature cuprate superconductors. Our approach is based on a novel strong-coupling Green's function expansion around a reference…
The thermal conductivity of organic superconductor kappa-(BEDT-TTF)2Cu(NCS)2 (Tc =10.4 K) has been studied in a magnetic field rotating within the 2D superconducting planes with high alignment precision. At low temperatures (T < 0.5 K), a…
In cuprate superconductors, the highest $T_c$ is possessed by the HgBa$_2$Ca$_2$Cu$_3$O$_{8+\delta}$ (Hg-1223) system at ambient pressure, but the reason remains elusive. Here we report the scanning tunneling measurements on the Hg-1223…
A major obstacle to understanding high-Tc cuprates is that superconductivity precludes observing normal-state properties at low temperatures. One prime example is the normal-state spin susceptibility \c{hi}spin: although its decrease upon…
25 years after discovery of high-temperature superconductivity (HTSC) in La$_{2-x}$Ba$_x$CuO$_4$ (LBCO), the HTSC continues to pose some of the biggest challenges in materials science. Cuprates are fundamentally different from conventional…
The pseudogap phenomenon in cuprates is the most mysterious puzzle in the research of high-temperature superconductivity. In particular, whether the pseudogap is associated with a crossover or phase transition has been a long-standing…
We report the successful synthesis of single-crystalline cuprate superconductors HgBa$_{2}$CaCu$_{2}$O$_{6+\delta}$ and HgBa$_{2}$Ca$_{2}$Cu$_{3}$O$_{8+\delta}$. These compounds are well-known for their high optimal superconducting critical…