Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSuperconductivity in a new layered nickel-selenide CsNi2Se2
131
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The physical properties of CsNi$_{2}$Se$_{2}$ were characterized by electrical resistivity, magnetization and specific heat measurements. We found that the stoichiometric CsNi$_{2}$Se$_{2}$ compound is a superconductor with a transition temperature textit{T$_{c}$}=2.7K. A large Sommerfeld coefficient $gamma$$_{n}$ ($sim$77.90 mJ/mol$cdot$K$^{-2}$), was obtained from the normal state electronic specific heat. However, the Kadowaki-Woods ratio of CsNi$_{2}$Se$_{2}$ was estimated to be about 0.041$times$10$^{-5}$ $muOmega$$cdot$cm(mol$cdot$K/mJ)$^{2}$, indicating the absence of strong electron-electron correlations in this compound. In the superconducting state, we found that the zero-field electronic specific heat data, $C_{es}(T)$ (0.5K $leq$ T $<$ 2.6K), can be well fitted with a two-gap BCS model. The comparison with the results of the density functional theory (DFT) calculations suggested that the large $gamma$$_{n}$ in the nickel-selenide superconductors may be related to the large Density of States (DOS) at the fermi surface.
rate research
Read More
Superconductivity has been discovered recently in nickel based 112 infinite thin films $R_{1-x}$A$_x$NiO$_2$ ($R$ = La, Nd, Pr and A = Sr, Ca). They are isostructural to the infinite-layer cuprate (Ca,Sr)CuO$_2$ and are supposed to have a formal Ni 3$d^9$ valence, thus providing a new platform to study the unconventional pairing mechanism of high-temperature superconductors. This important discovery immediately triggers a huge amount of innovative scientific curiosity in the field. In this paper, we try to give an overview of the recent research progress on the newly found superconducting nickelate systems, both from experimental and theoretical aspects. We will focus mainly on the electronic structures, magnetic excitations, phase diagrams, superconducting gaps and finally make some open discussions for possible pairing symmetries in Ni based 112 systems.
We report the superconductivity in layered oxychalcogenide La2O2Bi3AgS6 compound. The La2O2Bi3AgS6 compound has been reported recently by our group, which has a tetragonal structure with the space group P4/nmm. The crystal structure of La2O2Bi3AgS6 can be regarded as alternate stacks of LaOBiS2-type layer and rock-salt-type (Bi,Ag)S layer. We measured low-temperature electrical resistivity and observed superconductivity at 0.5 K. The observation of superconductivity in the La2O2Bi3AgS6 should provide us with the successful strategy for developing new superconducting phases by the insertion of a rock-salt-type chalcogenide layer into the van der Waals gap of BiS2-based layered compound like LaOBiS2.
Plasmonic excitations behave fundamentally different in layered materials in comparison to bulk systems. They form gapless modes, which in turn couple at low energies to the electrons. Thereby they can strongly influence superconducting instabilities. Here, we show how these excitations can be controlled from the outside via changes in the dielectric environment or in the doping level, which allows for external tuning of the superconducting transition temperature. By solving the gap equation for an effective system, we find that the plasmonic influence can both strongly enhance or reduce the transition temperature, depending on the details of the plasmon-phonon interplay. We formulate simple experimental guidelines to find plasmon- induced elevated transition temperatures in layered materials.
Superconductivity in low-dimensional compounds has long attracted much interest. Here we report superconductivity in a low-dimensional ternary telluride Ta4Pd3Te16 in which the repeating layers contain edge-sharing octahedrally-coordinated PdTe2 chains along the crystallographic b axis. Measurements of electrical resistivity, magnetic susceptibility and specific heat on the Ta4Pd3Te16 crystals, grown via a self-flux method, consistently demonstrate bulk superconductivity at 4.6 K. Further analyses of the data indicate significant electron-electron interaction, which allows electronic Cooper pairing in the present system.
We report on the phase diagram for charge-stripe order in La(1.6-x)Nd(0.4)Sr(x)CuO(4), determined by neutron and x-ray scattering studies and resistivity measurements. From an analysis of the in-plane resistivity motivated by recent nuclear-quadrupole-resonance studies, we conclude that the transition temperature for local charge ordering decreases monotonically with x, and hence that local antiferromagnetic order is uniquely correlated with the anomalous depression of superconductivity at x = 1/8. This result is consistent with theories in which superconductivity depends on the existence of charge-stripe correlations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
