Electron-phonon coupling in copper intercalated Bi[Formula: see text]Se[Formula: see text].

We report charge and heat transport studies in copper-intercalated topological insulator Bi[Formula: see text]Se[Formula: see text] hybrid devices. Measured conductivity shows impact of quantum corrections, electron-electron and electron-phonon interactions. Our shot noise measurements reveal that heat flux displays a crossover between [Formula: see text] and [Formula: see text] with the increase of temperature. The results might be explained by a model of inelastic electron scattering on disorder, increasing the role of transverse acoustic phonons in the electron-phonon coupling process.