Seebeck effect near quantum MIT in Eu sub(1-x)Ca sub(x)B sub(6)

• Published in: Physica Status Solidi. B: Basic Solid State Physics Vol. 250; no. 3; pp. 618 - 620
• Main Authors: Glushkov, Vladimir, Baybakov, Ruslan, Demishev, Sergey, Dukhnenko, Anatoliy, Levchenko, Anna, Shitsevalova, Natalya, Sluchanko, Nickolay
• Format: Journal Article
• Language: English
• Published: 01.03.2013
• Subjects: Band structure of solids; Calcium; Crossovers; Diffusion; Europium; Phonons; Seebeck effect; Solid state physics
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201200782

We report the results of a Seebeck effect study carried out on the single crystals of Eu sub(1-x)Ca sub(x)B sub(6) (0 less than or equal to x less than or equal to 1) at temperatures 1.8-300K. The Seebeck coefficient is shown to be determined by the sum of the linear term S=AT and a phonon-drag contribution, which is induced by the local phonon mode of europium (calcium) with the characteristic frequency 7.3meV (9.1meV). The crossover from negative (A approximately -0.23 mu VK super(-2) for x=0) to positive (A approximately +1.2 mu VK super(-2) for x=0.244) values of the diffusion thermopower indicates the smooth change of the band structure when approaching the hole-like conductivity found in Eu sub(1-x)Ca sub(x)B sub(6) at x>x sub(C) approximately 0.2.