Localized vibrational mode analysis of the resistivity and specific heat of LaB6 - art. no. 012302

LaB6 and other hexaborides are inclusion compounds in which the rare earth or other metal ion is weakly bound and sits in an oversized "cage" of boron ions. Here we show that a simple model that treats the La ions as independ ent harmonic (Einstein) oscillators embedded in a Debye framework of boron ions successfully accounts for the anomalies in the specific heat and resis tivity of LaB6. One of the nice features of the model is that the Einstein temperature of the La atoms and the Debye temperature of the boron framewor k are derived from room-temperature x-ray crystallography data. This featur e makes the model easy to apply to other hexaborides and other materials th at can be treated as inclusion compounds. The results from this work imply that local modes are likely to be important for understanding the physical properties of all the hexaborides.