Fig. 2

Tilted vortex cores vs. bias voltage. In a–e we show conductance maps for bias voltages of 0 mV (a), 0.2 mV (b), 0.4 mV (c), 0.6 mV (d), 0.8 mV (e). Left panels show conductance maps with a field of 0.6 T parallel to the c axis. Middle and right panels show conductance maps at nearly parallel magnetic fields (θ ≈ 90° with an uncertainty of a few degrees). In the middle panels, the in-plane tilt is with the azimuthal angle along a crystalline direction (φ = 0) and in the right panels in between crystalline directions (φ = 30°). The in-plane direction of the tilt is shown by the red arrows in middle and right panels of a. Scale bars are of 30 nm in the left panels and 120 nm in middle and right panels. The color scale is given by the bar in a. The vortex density decreases for nearly parallel magnetic fields. The stripes at mostly visible at zero bias and follow the in-plane direction of the magnetic field in a. At high bias, the stripes are no longer present. Vortices present  elongated shapes and are strongly in-plane asymmetric, with a clear yellow-blue pattern along the in-plane direction of the magnetic field (e, middle and right panels).