Related papers: Quasiparticle evolution and pseudogap formation in…
Infrared reflectivity measurements of CeSb under multi-extreme conditions (low temperatures, high pressures and high magnetic fields) were performed. A pseudo gap structure, which originates from the magnetic band folding effect,…
In this study, we conducted various magnetotransport measurements on Fe$_{1+y}$Te$_{1-x}$Se$_{x}$ single crystals from which excess iron was sufficiently removed. Our results revealed that crossover from the incoherent to the coherent…
The relationship between the pseudogap and superconductivity remains a central puzzle in the physics of cuprates. Hydrostatic pressure provides a clean tuning parameter free from chemical disorder, yet probing the microscopic energy scales…
We report the in-plane optical measurements on Na$_x$CoO$_2$ with 0.18$\leq$x$\leq$0.92. The crystal growth and characterization were described in detail. The spectral weight increases monotonically with decreasing x. For sample with the…
The magnitude and the temperature dependence of the superconducting order parameter {\Delta}(T) of single-crystals of Cd2Re2O7 (Tc = 1.02 K) was measured using point contact spectroscopy. In order to fit the conductance spectra and to…
We studied the temperature dependences of the optical spectra for optimally and underdoped Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+z}$ single crystals. Similarly to the other cuprates' cases, a gap-like conductivity suppression was observed with…
Optical reflectivity study has been made on the hexagonal (NiAs-type) Ni_{1-d}S in order to probe its electronic properties, in particular those associated with the metal-nonmetal transition in this compound. Samples with d=0.005 and 0.02…
The onset of the pseudogap in high-$T_c$ superconducting cuprates (HTSC) is marked by the $T^*$ line in the doping-temperature phase diagram, which ends at a point $p^*$ at zero temperature within the superconducting dome. Although various…
We consider the motion of conductivity spectral weight at a finite-temperature phase transition at which $d_{x^2-y^2}$ density-wave (DDW) order develops. We show that there is a shift of spectral weight to higher frequencies if the…
Using a combination of spectroscopic ellipsometry and DC transport measurements, we determine the temperature dependence of the optical conductivity of NdNiO$_3$ and SmNiO$_{3}$ films. The optical spectra show the appearance of a…
The transport experiments reveal that the low-temperature resistivity in the normal-state of cuprate superconductors is quadratic in temperature (T-quadratic) in the underdoped pseudogap phase, while it is linear in temperature (T-linear)…
We show by means of the theory of the order parameter phase fluctuations that the temperature of "closing" (or "opening") of the gap (and pseudogap) in the electron spectra of superconductors with anisotropic order parameter takes place…
Vanadium is a transition metal with multiple oxidation states and V2O5 is the most stable form among them. Besides catalysis, chemical sensing and photo-chromatic applications, V2O5 is also reported to exhibit a semiconductor to metal…
The gap function in unconventional superconductors may vanish at points or lines in momentum space, permitting electronic excitations, termed nodal quasiparticles, to exist at temperatures well below the superconducting transition. In the…
We propose a new approach to understand the origin of the pseudogap in the cuprates, in terms of bosonic entropy. The near-simultaneous softening of a large number of different $q$-bosons yields an extended range of short-range order,…
We utilize ultrafast optical measurement to study the quasiparticle relaxation in stoichiometric LiFeAs and nearly optimally doped (BaK)Fe2As2 crystals. According to our temperature-dependent studies of LiFeAs, we have observed…
The mechanism of high temperature superconductivity is not resolved for so long because the normal state of cuprates is not yet understood. Here we show that the normal state pseudo-gap exhibits an unexpected non-monotonic temperature…
We study two Heisenberg-Kitaev t-J-like models on a honeycomb lattice, focusing on the zigzag magnetic phase of Na$_2$IrO$_3$, and investigate hole motion by exact diagonalization and variational methods. The spectral functions are quite…
The optical properties of a V4O7 single crystal have been investigated from the high temperature metallic phase down to the low temperature antiferromagnetic insulating one. The temperature dependent behavior of the optical conductivity…
We study the nonlinear transport properties of NS (normal-superconductor) and NSN structures by means of a self-consistent microscopic description. A nonzero superfluid velocity causes the various quasiparticle channels within S to open at…