Fig. 5

Non-monotonic pressure dependence of κ⁽³⁺⁴⁾ in BSb. Pressure-temperature colormap of κ⁽³⁺⁴⁾ of isotopically pure BSb scaled by the corresponding zero-pressure value at each temperature \(\left( {\kappa _{0}^{(3 + 4)}} \right)\), similar to the plot for BAs in Fig. 4a. BSb, also being a large mass-ratio compound like BAs, is strongly affected by four-phonon scattering and shows a qualitatively similar pressure-dependent non-monotonicity of thermal conductivity like BAs