Investigation of infrared spectra and determination of the main optical constants, of CaB6

Tsebulya, G. G.; Kozina, Goran; Zakharchuk, A. P.; Kovalev, A. V.; Dudnik, E. M.

doi:10.1007/bf02676003

Cited by 3 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Quite generally, R() is lower for the Ca-deficient crystal in the visible and UV spectral ranges, where the electronic interband transitions develop ͑see below͒. Our spectra for both CaB 6 crystals are distinctly different from previously published results, obtained by Tsebulya et al 15 on a CaB 6 single crystal in a limited spectral range and revealing the onset of a plasma edge around 3500 cm Ϫ1 . At present, we do not know the origin of this discrepancy.…”

Section: Optical Propertiescontrasting

confidence: 94%

Electronic transport and thermal and optical properties ofCa1−xLax

et al. 2000

View full text Add to dashboard Cite

We present a study of transport, thermal, and optical properties of stoichiometric CaB 6 and La-doped CaB 6 . For stoichiometric CaB 6 a strong increase of the resistivity with decreasing temperature and anomalies in the low-temperature behavior of the resistivity and the specific heat have been observed. The application of an external magnetic field at low temperatures is shown to lead to an anomalous magnetoresistance in the case of stoichiometric CaB 6 . The optical conductivity exhibits a strong doping dependence. Rather unexpectedly, small changes in the chemical composition lead to significant changes in the electronic interband transitions in the visible-UV spectral range. The relevance of our results with respect to the recently suggested excitonic scenario for explaining the physical properties of alkaline-earth hexaborides is discussed. PHYSICAL REVIEW B15 OCTOBER 2000-I VOLUME 62, NUMBER 15 PRB 62

show abstract

Section: Optical Propertiescontrasting

confidence: 94%

Electronic transport and thermal and optical properties ofCa1−xLax

et al. 2000

View full text Add to dashboard Cite

show abstract

“…These results are in contrast to earlier reports in Ref. 16 ͑a high-alloy semiconductor model͒ and Ref. 17 ͑a doped semimetal model͒ but are compatible with Ref.…”

contrasting

confidence: 71%

Formation of midgap states and ferromagnetism in semiconductingCaB6

Cho

Rhyee

et al. 2004

Phys. Rev. B

View full text Add to dashboard Cite

We present a consistent overall picture of the electronic structure and ferromagnetic interaction in CaB 6 , based on our joint transport, optical, and tunneling measurements on high-quality defect-controlled single crystals. Pure CaB 6 single crystals, synthesized with 99.9999% pure boron, exhibited fully semiconducting characteristics, such as monotonic resistance for 2-300 K, a tunneling conductance gap, and an optical absorption threshold at 1.0 eV. Boron-related defects formed in CaB 6 single crystals synthesized with 99.9% pure boron induced midgap states 0.18 eV below the conduction band and extra free charge carriers, with the transport, optical, and tunneling properties substantially modified. Remarkably, no ferromagnetic signals were detected from single crystals made with 99.9999% pure boron, regardless of stoichiometry, whereas those made with 99.9% boron exhibited ferromagnetism within a finite range of carrier density. The possible surmise between the electronic state and magnetization will be discussed.

show abstract