Electronic Fine Structure in the Electron-Hole Plasma in SrB6

C. O. RODRIGUEZ; RUBEN WEHT; WARREN E. PICKETT

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2000 vol. 84 p. 3903 - 3906

0031-9007

Electron-hole mixing-induced fine structure in alkaline earth hexaborides leads to lower energy (temperature) scales, and thus a stronger tendency toward an excitonic instability than in their doped counterparts (viz. Ca12x Lax B6 , x ഠ 0.005͒, which are high-Curie-temperature, small-moment ferromagnets. Comparison of Fermi surfaces and spectral distributions with de Haas – van Alphen, optical, transport, and tunneling data indicates that SrB6 remains a fermionic semimetal down to (at least) 5 K, rather than forming an excitonic condensate. For the doped system the Curie temperature is higher than the degeneracy temperature.