Formation and properties of SrB6 single crystals synthesized under high pressure and temperature

Highlights: → We adopt a novel method-high temperature high pressure to synthesize SrB6 single crystals. → Electric resistivity measurement resolved the debates on the electronically conductive nature of SrB6. → Magnetization measurement resolved the debates on the origin of the unusual magnetism of SrB6. - Abstract: Pure SrB6 single crystals are synthesized under high pressure (5 GPa) and temperature (1300 deg. C). The structure and morphology of the SrB6 single crystals are characterized by X-ray diffraction and field emission scanning electron microscope. The lattice constant of the SrB6 crystals with a space group of Pm-3m is a = 4.1975 A. The dependence of electric resistivity and Hall coefficient on temperatures from 2 to 300 K show that the SrB6 single crystals are conductive materials with semi-metallic behavior and can be considered as electronic current carriers. The results of the band structure calculation show that the conduction and valence bands meet at the X point at the Fermi Level, which is consistent with the experimentally measured conducting behavior of SrB6 single crystals. The total and partial density of states show that the states at the Fermi level come from the 2p orbitals of the B atoms and the 4d orbital of the Sr atom. The magnetization measurement shows the diamagnetic nature of the SrB6. The nanoindentation measurement indicates that the hardness of SrB6 reached 33 GPa.