Related papers: Quantum critical scaling and superconductivity in …
The phenomena of superconductivity and superfluidity are believed to originate from the same underlying physics, namely the condensation of either bosons or pairs of fermions (Cooper pairs). In this work I complied and analyzed literature…
The thermally driven confinement-deconfinement transition exhibited by lattice quantum electrodynamics in two space dimensions is re-examined in the context of the statistical gauge-fields common to anyon superconductors and to…
By using transport and magnetic measurement, the upper critical field $H_{c2}(T)$ and the irreversibility line $H_{irr}(T)$ has been determined. A big separation between $H_{c2}(0)$ and $H_{irr}(0)$ has been found showing the existence of a…
We report a precise $^{59}$Co nuclear quadrupolar resonance (NQR) measurement on the recently discovered cobalt oxyhydrate Na$_{0.35}$CoO$_{2}$$\cdot y$H$_{2}$O superconductor from $T$=40 K down to 0.2 K. We find that in the normal state…
We show that there are strong similarities in the spin lattice relaxation of non-magnetic organic charge transfer salts, and that these similarities can be understood in terms of spin fluctuations. Further, we show that, in all of the…
The transverse field Ising chain (TFIC) model is ideally suited for testing the fundamental ideas of quantum phase transitions, because its well-known $T=0$ ground state can be extrapolated to finite temperatures. Nonetheless, the lack of…
We performed $^{13}$C-NMR experiment and measured spin-lattice relaxation rate divided by temperature $1/T_{1}T$ near the superconducting (SC) transition temperature $T_{c}$ in $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Br ($\kappa$-Br salt),…
We demonstrate quantum critical scaling for an $S=1/2$ Heisenberg antiferromagnetic chain compound CuPzN in a magnetic field around saturation, by analysing previously reported magnetization [Y. Kono {\it et al.}, Phys. Rev. Lett. {\bf…
Quantum-mechanical fluctuations between competing phases at $T=0$ induce exotic finite-temperature collective excitations that are not described by the standard Landau Fermi liquid framework. These excitations exhibit anomalous temperature…
We performed high-field magnetization, magnetocaloric effect (MCE), and NMR measurements on the Ising triangular-lattice antiferromagnet Rb$_2$Co(SeO$_3$)$_2$. The observations of the 1/3-magnetization plateau, the split NMR lines, and the…
Several elements in the periodic table exhibit an interesting and often overlooked feature: They skip certain valence states which is discussed in the field of superconductivity to be in favor of fostering higher transition temperatures…
We present a high-pressure NMR study of the overdoped iron pnictide superconductor NaFe$_{0.94}$Co$_{0.06}$As. The low-energy antiferromagnetic spin fluctuations in the normal state, manifest as the Curie-Weiss upturn in the spin-lattice…
We present lattice results for baryon number, strangeness and electric charge fluctuations as well as their correlations at finite temperature and vanishing chemical potentials, i.e. under conditions relevant for RHIC and LHC. We find that…
We report on high-pressure (p_max = 2.1 GPa) muon spin rotation experiments probing the temperature-dependent magnetic penetration depth in the layered superconductor 2H-NbSe_2. Upon increasing the pressure, we observe a substantial…
The quantum spin fluctuations of the S = 1/2 Cu ions are important in determining the physical properties of the high-transition temperature (high-Tc) copper oxide superconductors, but their possible role in the electron pairing for…
Overdoped cuprate superconductors are strange metals above their superconducting transition temperature. In such materials, the electrical resistivity has a strong linear dependence on temperature ($T$) and electrical current is not carried…
Motivated by recent experiments reporting superconductivity only at very low temperature in a class of heavy fermion compounds, we study the impact of energy fluctuations with small momentum transfer on the pairing instability near an…
When a second-order magnetic phase transition is tuned to zero temperature by a non-thermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these `quantum…
Quantum criticality has been invoked as being essential to the understanding of a wide range of exotic electronic behavior, including heavy Fermion and unconventional superconductivity, but conclusive evidence of quantum critical…
We used transport and inelastic neutron scattering to study the optimally phosphorus-doped BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$ superconductor ($T_c = 30$ K). In the normal state, we find that the previously reported linear temperature…