Session 6-2

Abstract

Thermal properties of solids are largely governed by phonons. The measurement and understanding of phonon properties at heterointerfaces and lattice defects at nanometer scales are an important issue for controlling phonon transport in various devices. Using a monochromated electron microscope and electron energy loss spectroscopy (EELS) as shown in Fig. 1 [1, 2], we obtained (i) nanometer-scale phonon dispersion, (ii) phonon mode mapping in a heterojunction (Fig. 2a), and (iii) vibrational mode localized at the heterointerface (Fig. 2b). We also demonstrated (iv) nanometer-scale temperature measurement using EELS and the principle of detail balancing between creation and annihilation of phonons [3]. This thermometry scheme was applied to evaluate (v) the local temperature in a nanowire during Joule heating.