Spectroscopy Of Superconductors Research Articles

Bogoliubov angle, particle-hole mixture, and angle-resolved photoemission spectroscopy in superconductors

Superconducting state is characterized by excitations---Bogoliubov quasiparticles that represent a coherent mixture of electron $(\ensuremath{-}e)$ and hole $(+e)$ components. We propose an observable, which we call Bogoliubov angle, which can be extracted using angular resolved photoemission spectroscopy (ARPES) and reveal this particle-hole entanglement by measuring relative weight of particle and hole amplitude of the Bogoliubov quasiparticle. This angle can be measured using the ratio of ARPES spectral intensities at positive and negative energies. Bogoliubov angle could be used to identify variety of possible pairing states and for discussion on possible nature of the pseudogap states that could contain pairing correlations.

Femtosecond time-domain spectroscopy of superconductors and charge-density-wave systems

Femtosecond time-domain spectroscopy of superconductors and charge-density-wave systems

On the problem of zero-bias anomalies in the tunneling spectroscopy of superconductors

Taking into account nonmagnetic energy-loss processes in the barrier as a model for zero-bias anomalies, we derive an expression for the derivative of the tunneling current with respect to the applied voltage as a function of the superconducting density of states in a superconductor-normal metal junction. It is assumed that boson-like excitations are created in the barrier region. The investigations show, that the results of elastic tunneling calculations have to be corrected by a term proportional to an integral over the superconducting density of states.