0000000000314918
AUTHOR
J. Demsar
Melting the Superconducting State in the Electron Doped Cuprate Pr$_{1.85}% $Ce$_{0.15}$CuO$_{4-\delta}$ with Intense near-infrared and Terahertz Pulses
We studied the superconducting (SC) state depletion process in an electron doped cuprate Pr$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$ by pumping with near-infrared (NIR) and narrow-band THz pulses. When pumping with THz pulses tuned just above the SC gap, we find the absorbed energy density required to deplete superconductivity, $A_{dep}$, matches the thermodynamic condensation energy. Contrary, by NIR pumping $A_{dep}$ is an order of magnitude higher, despite the fact that the SC gap is much smaller than the energy of relevant bosonic excitations. The result implies that only a small subset of bosons contribute to pairing.
Robust hybridization gap in a Kondo Insulator YbB${}_{12}$ probed by femtosecond optical spectroscopy
In heavy fermions the relaxation dynamics of photoexcited carriers has been found to be governed by the low energy indirect gap, E$_{g}$, resulting from hybridization between localized moments and conduction band electrons. Here, carrier relaxation dynamics in a prototype Kondo insulator YbB${}_{12}$ is studied over large range of temperatures and over three orders of magnitude. We utilize the intrinsic non-linearity of dynamics to quantitatively determine microscopic parameters, such as electron-hole recombination rate. The extracted value reveals that hybridization is accompanied by a strong charge transfer from localized 4f-levels. The results imply the presence of a hybridization gap up…
N\'{e}el Spin Orbit Torque driven antiferromagnetic resonance in Mn$_{2}$Au probed by time-domain THz spectroscopy
We observe the excitation of collective modes in the THz range driven by the recently discovered N\'{e}el spin-orbit torques (NSOT) in the metallic antiferromagnet Mn$_{2}$Au. Temperature dependent THz spectroscopy reveals a strong absorption mode centered near 1 THz, which upon heating from 4 K to 450 K softens and looses intensity. Comparison with the estimated eigenmode frequencies implies that the observed mode is an in-plane antiferromagnetic resonance (AFMR) mode. The AFMR absorption strength exceeds those found in antiferromagnetic insulators, driven by the magnetic field of the THz radiation, by three orders of magnitude. Based on this and the agreement with our theory modelling, we…