Electron Tunneling Spectroscopy of the Anisotropic Kitaev Quantum Spin Liquid Sandwiched with Superconductors

Abstract

We present the electron tunneling transport and spectroscopic characters of a superconducting Josephson junction with a barrier of single Kitaev quantum spin liquid (QSL) layer. We find that the dynamical spin correlation features are well reflected in the direct current differential conductance dI c /dV of the single-particle tunneling with an energy shift of superconducting gap sum 2∆, including the unique spin gap and dressed itinerant Majorana dispersive band, which can be regarded as evidence of the Kitaev QSL. However, the zero-voltage Josephson current I s only displays some residual features of dynamical spin susceptibility in the Kitaev QSL due to the spin singlet of Cooper pairs. These results pave a new way to measure the dynamical spinon or Majorana fermion spectroscopy of the Kitaev and other spin liquid materials.

Resonant Inelastic X-ray Scattering from Electronic Excitations in $α$-RuCl$_3$ Nanolayers

“…These developments raise the prospect of studying magnetism in the 2D limit, without the influence of the interlayer interactions that are found to have a non-negligible influence on the magnetic structure of bulk RuCl 3 [26,27]. They also open up perspectives for targeted modification of the electronic properties, for instance by doping charge carriers into the correlated pseudospin system via doping across heterointerfaces, or by interfacial proximity coupling to other quantum states such as superconductivity [28][29][30][31].…”