Predicted low thermal conductivities in antimony films and the role of chemical functionalization

Chemical functionalization is an effective means of tuning the electronic and crystal structure of a two-dimensional material, but very little is known regarding the correlation between thermal transport and chemical functionalization. Based on the first-principles calculation and an iterative solution of the Boltzmann transport equation, we find that antimonene is a potential excellent thermal material with relatively low thermal conductivity k, and furthermore, chemical functionalization can make this value of k decrease greatly. More interestingly, the origin of the reduction in k is not the anharmonic interaction but the harmonic interaction from the depressed phonon spectrum mechanism, and for some chemical functional atom in halogen, flat modes appearing in the low frequency range play also a key factor in the reduction of k by significantly increasing the three-phonon scattering channels. Our work provides a new view to adjust thermal transport which can benefit thermal material design, and analyzes the reduction mechanism in k from the chemical functionalization of antimonene.