Extremely low thermal conductivity in 1D soft chain structure BiSeX (X = Br, I)

Researchers found a new sort of simple one-dimensional (1D) crystal structured bismuth selenohalides (BiSeX, X = Br, I) with extremely low thermal conductivity. Investigations on crystal structure reveal that the ultralow thermal conductivity is due to the weakened chemical bonding in the low-dimensional structure, showing a quasi-0D crystal structure. These findings provide a novel selection rule to search low thermal conductivity materials with potential applications in thermoelectrics and thermal barrier coatings.