arXiv subjects

Pei-Herng Hor

Publications and source records attributed to Pei-Herng Hor.

3 recordsLinked to original sources

arXiv2015

Quantitative connection between the nanoscale electronic inhomogeneity and the pseudogap of Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ superconductors

We have found a quantitative connection between the evolution of the inhomogeneous nanoscale electronic gaps (INSEG) state detected in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ by scanning tunneling microscopy/spectroscopy (STM/S) and the two universal, the upper and the lower, pseudogaps in high-temperature cuprate superconductors (HTCS). When the doping and temperature dependent INSEG map were analyzed by using our proposed hole-scale, we find that the two pseudogaps are connected to two specific coverages of the CuO$_2$ plane by INSEG: the 50\% and 100\% coverages of the CuO$_2$ planes by INSEG correspond to the upper and lower pseudogaps, respectively. This quantitative connection to the two pseudogaps indicates that the origin of the measured pseudogap energies and temperatures are intimately related to the geometrical coverage of the CuO$_2$ planes by the INSEG state. We find that INSEG and superconductivity coexist in the underdoped to the overdoped regimes. We suggest that pseudogap states are microscopically inhomogeneous and 100\% coverage of the CuO$_2$ planes by the INSEG is a necessary condition for the high-$T_c$ superconductivity.

cond-mat.supr-con↗

arXiv2011

Energy-Dependent Enhancement of the Electron-Coupling Spectrum of the Underdoped Bi2Sr2CaCu2O8+d Superconductor

We have determined the electron-coupling spectrum of superconducting Bi2Sr2CaCu2O8+d from high-resolution angle-resolved photoemission spectra by two deconvolution-free robust methods. As hole concentration decreases, the coupling spectral weight at low energies ~<15 meV shows a twofold and nearly band-independent enhancement, while that around ~65 meV increases moderately, and that in ~>130 meV decreases leading to a crossover of dominant coupling excitation between them. Our results suggest the competition among multiple screening effects, and provide important clues to the source of sufficiently strong low-energy coupling, λLE ~ 1, in underdoped system.

cond-mat.supr-con↗

arXiv2010

Universal scaling of c-axis dc conductivity for the underdoped hightemperature cuprate superconductors

Coexistence of the "metallic-like" in-plane and the "semiconducting-like" out-of-plane (caxis) dc conductivities (σc), generating a huge anisotropy in the underdoped hightemperature cuprate superconductors (HTCS), defies our current understanding of metal. In this report we present an intrinsic doping dependence of σc. We find that the σc for the underdoped HTCS is universally scaled to the σc at the optimal doped-hole concentration. The universal scaling behavior suggests that there are three intrinsic processes contribute to σc: (i) the doping-dependent-activated gap; (ii) the exponential doping dependences and (iii) the tunneling between adjacent CuO2 block layers. They are the essential underlying characteristics of the c-axis transport for all HTCSs.

cond-mat.supr-con↗