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Thickness Effects on Crystal Growth and Metal–Insulator Transition in Rutile‐Type RuO 2 (100) Thin Films
Author(s) -
Kutsuzawa Dai,
Oka Daichi,
Fukumura Tomoteru
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000188
Subject(s) - rutile , materials science , condensed matter physics , electrical resistivity and conductivity , variable range hopping , metal–insulator transition , thermal conduction , thin film , metal , composite material , nanotechnology , chemistry , metallurgy , electrical engineering , physics , organic chemistry , engineering
The thickness dependence of crystal structure and electrical properties is studied for rutile‐type RuO 2 (100) thin films. The island growth mode results in a monotonically varying lattice strain along the a ‐axis from negative to positive with increasing thickness. Decrease in the thickness below 20 nm increases the resistivity drastically, resulting in insulating‐like behaviors. The metallic behaviors of the thicker films are well explained by the modified Bloch–Grüneisen function as in bulk RuO 2 , where the strain has a significant influence on the conduction parameters. The insulating‐like behaviors of the thinner films are assigned to 2D localization and Mott variable range hopping, reflecting the effects of the size and growth mode on electrical conduction.