Longitudinal conductivity of LaF3/SrF2 multilayer heterostructures

Science and Technology of Advanced Materials

Alexander Banshchikov¹  Nikolay Sokolov¹  Marc Christopher Wurz²  Alexey Filimonov³  Tikhon Vergentev³  Ekaterina Koroleva³ 

[1] Divisions of Solid State Physics and Physics of Dielectric and Semiconductors, Ioffe Institute;Institute for Microproduction Technology, Leibniz University of Hanover;Institute of Physics, Nanotechnology and Telecommunications, Peter the Great St. Petersburg Polytechnic University;

关键词: impedance spectroscopy;    ionic conductivity;    lanthanum fluoride;    strontium fluoride;    molecular beam epitaxy;    heterostructures;    longitudinal conductivity;    interfacial spacing;   

DOI  :  10.1080/14686996.2016.1246940

来源: DOAJ

【 摘 要 】

LaF3/SrF2 multilayer heterostructures with thicknesses of individual layers in the range 5–100 nm have been grown on MgO(100) substrates using molecular beam epitaxy. The longitudinal conductivity of the films has been measured using impedance spectroscopy in the frequency range 10−1–106 Hz and a temperature range 300–570 K. The ionic DC conductivities have been determined from Nyquist impedance diagrams and activation energies from the Arrhenius–Frenkel equation. An increase of the DC conductivity has been observed to accompany decreased layer thickness for various thicknesses as small as 25 nm. The greatest conductivity has been shown for a multilayer heterostructure having thicknesses of 25 nm per layer. The structure has a conductivity two orders of magnitude greater than pure LaF3 bulk material. The increasing conductivity can be understood as a redistribution of charge carriers through the interface due to differing chemical potentials of the materials, by strong lattice-constant mismatch, and/or by formation of a solid La1-xSrxF3-x solution at the interface during the growth process.

【 授权许可】

Unknown