arXiv subjects

K. F. Zhang

Publications and source records attributed to K. F. Zhang.

3 recordsLinked to original sources

arXiv2014

Fully Gapped s-wave-like Superconducting State and Electronic Structures in the Ir0.95Pd0.05Te2 Single Crystals with Strong Spin-orbital Coupling

Due to the large spin-orbital coupling in the layered 5d-transition metal chalcogenides compound, the occurrence of superconductivity in Ir2-xPdxTe2 offers a good chance to search for possible topological superconducting states in this system. We did comprehensive studies on the superconducting properties and electronic structures of single crystalline Ir0.95Pd0.05Te2 samples. The superconducting gap size, critical fields and coherence length along different directions were experimentally determined. Macroscopic bulk measurements and microscopic low temperature scanning tunneling spectroscopy results suggest that Ir0.95Pd0.05Te2 possesses a BCS-like s-wave state. No sign of zero bias conductance peak were found in the vortex core at 0.4K.

cond-mat.supr-con↗

arXiv2005

The Evolution of Universe with th B-I Type Phantom Scalar Field

We considered the phantom cosmology with a lagrangian $\displaystyle L=\frac{1}η[1-\sqrt{1+ηg^{μν}ϕ_{, μ}ϕ_{, ν}}]-u(ϕ)$, which is original from the nonlinear Born-Infeld type scalar field with the lagrangian $\displaystyle L=\frac{1}η[1-\sqrt{1-ηg^{μν}ϕ_{, μ}ϕ_{, ν}}]-u(ϕ)$. This cosmological model can explain the accelerated expansion of the universe with the equation of state parameter $w\leq-1$. We get a sufficient condition for a arbitrary potential to admit a late time attractor solution: the value of potential $u(X_c)$ at the critical point $(X_c,0)$ should be maximum and large than zero. We study a specific potential with the form of $u(ϕ)=V_0(1+\fracϕ{ϕ_0})e^{(-\fracϕ{ϕ_0})}$ via phase plane analysis and compute the cosmological evolution by numerical analysis in detail. The result shows that the phantom field survive till today (to account for the observed late time accelerated expansion) without interfering with the nucleosynthesis of the standard model(the density parameter $Ω_ϕ\simeq10^{-12}$ at the equipartition epoch), and also avoid the future collapse of the universe.

hep-th↗

arXiv2004

Dark Energy and Dilaton Cosmology

We studied the dilaton cosmology based on Weyl-Scaled induced gravity. The potential of dilaton field is taken as exponential form. An analytical solution of Einstein equation is found. The dilaton can be a candidate for dark energy that can explain the accelerated universe. The structure formation is also considered. We find the the evolutive equation of density perturbation, and its growth is quicker than the one in standard model which is consistent with the constraint from CMBR measurements

hep-th↗