Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisiting the vortex-core tunnelling spectroscopy in
  YBa$_2$Cu$_3$O$_{7-\delta}$   The observation by scanning tunnelling spectroscopy (STS) of Abrikosov vortex
cores in the high-temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$ (Y123)
has revealed a robust pair of electron-hole symmetric states at finite subgap
energy. Their interpretation remains an open question because theory predicts a
different signature in the vortex cores, characterised by a strong zero-bias
conductance peak. We present STS data on very homogeneous Y123 at 0.4 K
revealing that the subgap features do not belong to vortices: they are actually
observed everywhere along the surface with high spatial and energy
reproducibility, even in the absence of magnetic field. Detailed analysis and
modelling show that these states remain unpaired in the superconducting phase
and belong to an incoherent channel which contributes to the tunnelling signal
in parallel with the superconducting density of states.

15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga