96 research outputs found
Effect of Doping on the phase stability and Superconductivity in LaH10
We present a computational investigation into the effects of chemical doping
with 15 different elements on phase stability and superconductivity in the
LaH10 structure. Most doping elements were found to induce softening of phonon
modes, enhancing electron-phonon coupling and improving critical
superconducting temperature while weakening dynamical stability. Unlike these
dopants, Ce was found to extend the range of dynamical stability for LaH10 by
eliminating the van Hove singularity near the Fermi level. The doped compound,
La0.75Ce0.25H10, maintains high-temperature superconductivity. We also
demonstrate that different Ce doping configurations in the LaH10 structure have
a minimal effect on energetic stability and electron-phonon coupling strength.
Our findings suggest that Ce is a promising dopant to stabilize LaH10 at lower
pressures while preserving its high-temperature superconductivity
Reconfigurable Intelligent Surface Aided Space Shift Keying With Imperfect CSI
In this paper, we investigate the performance of reconfigurable intelligent
surface (RIS)-aided spatial shift keying (SSK) wireless communication systems
in the presence of imperfect channel state information (CSI). Specifically, we
analyze the average bit error probability (ABEP) of two RIS-SSK systems
respectively based on intelligent reflection and blind reflection of RIS. For
the intelligent RIS-SSK scheme, we first derive the conditional pairwise error
probability of the composite channel through maximum likelihood (ML) detection.
Subsequently, we derive the probability density function of the combined
channel. Due to the intricacies of the composite channel formulation, an exact
closed-form ABEP expression is unattainable through direct derivation. To this
end, we resort to employing the Gaussian-Chebyshev quadrature method to
estimate the results. In addition, we employ the Q-function approximation to
derive the non-exact closed-form expression when CSI imperfections are present.
For the blind RIS-SSK scheme, we derive both closed-form ABEP expression and
asymptotic ABEP expression with imperfect CSI by adopting the ML detector. To
offer deeper insights, we explore the impact of discrete reflection phase
shifts on the performance of the RIS-SSK system. Lastly, we extensively
validate all the analytical derivations using Monte Carlo simulations.Comment: arXiv admin note: text overlap with arXiv:2307.0199
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