Boron 10B—11B Isotope Substitution as a Probe of the Mechanism Responsible for the Record Thermionic Emission in LaB6 with the Jahn—Teller Instability1
| Autor: | N. Yu. Shitsevalova, V. Voronov, Yurii A Aleshchenko, A. V. Muratov, Mikhail A. Anisimov, G. A. Komandin, Martin Dressel, M. A. Belyanchikov, V. B. Filipov, Boris Gorshunov, N. E. Sluchanko, Z. V. Bedran, Anatoliy V. Dukhnenko, Elena S. Zhukova |
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| Rok vydání: | 2019 |
| Předmět: |
Electron density
Materials science Physics and Astronomy (miscellaneous) Solid-state physics Jahn–Teller effect Thermionic emission Electron Isotopes of boron Lanthanum hexaboride 01 natural sciences 010305 fluids & plasmas chemistry.chemical_compound chemistry 0103 physical sciences Charge carrier Atomic physics 010306 general physics |
| Zdroj: | JETP Letters. 110:79-84 |
| ISSN: | 1090-6487 0021-3640 |
| DOI: | 10.1134/s0021364019130058 |
| Popis: | We have tested the conduction band electrons of lanthanum hexaboride that is among the most effective electron-beam sources with one of the highest brightness of thermionic emission. We performed infrared spectroscopic, DC (direct current) resistivity and Hall-effect studies of LaB6 single crystals with various 10B and 11B isotope contents. We find that only a small amount of conduction electrons behave as Drude-type charge carriers while about 70% of the electrons are involved in collective oscillations of electron density coupled to vibrations of both the Jahn-Teller unstable rigid boron cage and rattling modes of La-ions loosely bound to the lattice. We suggest that exactly these non-equilibrium conduction electrons determine the extraordinary low work function of thermoemission in LaB6. |
| Databáze: | OpenAIRE |
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