Fig. 2: Anisotropic in-plane magnetic field effects on the thermal conductivity.

Panels a–c, plot the normalized κ(B) profiles of different combinations of (∇T, B) orientations at selected temperatures. The purple curves and the green curves depict the data collected with field increasing and decreasing, respectively. All κ(B) curves experience a saturation at high fields, signaling that a polarized state was reached in this study. Panels a and b depict the results of the same crystal (Sample#1) with the same ∇T orientation (∇T ∥ zigzag) but with different B directions. They behave fundamentally different. Meanwhile, Panel b resembles Panel c which is the data collected from another crystal (Sample#2) with a different ∇T orientation (∇T ∥ armchair) but the same field direction (B ∥ armchair). As highlighted in the inset of Panel c, an oscillation-like feature can be distinguished before an abrupt increase of the κ(B) for the field-up ramp. The anomalies in all κ/T(B) curves are marked by different symbols. d The temperature evolution of these anomalies of κ(B) profiles in the “spin disordered" state and field polarized state, as indicated by the colored arrow above the panel. They are grouped into different categories as glided by the background stripes. The field values for Sample#2 are multiplied by 96%, in order to compromise the possible (out-of-plane) misalignment.