1. Nanoelectronics Research Institute, AIST, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Japan
2. Institute of Thermophysics of the Russian Academy of Sciences, Lavrentyev Ave. 1, and Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia