| Abstract: | The electrical properties of polycrystalline CaB_6 are revealed by in-situ resistance measurements under high pressure and low temperature.Due to the existence of grain boundaries,polycrystalline CaBe behaves with semiconducting transport properties,which is different from the semimetallic CaBe single crystals.The temperaturedependent resistance measurement results show that before the structural phase transition at 12.3 GPa the high pressure first induces the metallization at 6.5 GPa for CaBe.Moreover,the phase diagram for CaB_6 is drawn based on the investigated electric conducting properties and at ieast three different conducting phases are found even at moderate high pressure and low temperature,indicating that the electric nature of CaBe is very sensitive to the environment. |
