Thermochemical Hole Burning on TEA(TCNQ)2 Single Crystal at Varied Temperatures in UHV System

Abstract

The present article investigates a thermochemical hole burning (THB) effect on a charge transfer (CT) complex, triethylammonium bis-7,7,8,8-tetracyanoquinodimethane [TEA(TCNQ)2] in an ultrahigh vacuum (UHV) system with a variable temperature scanning tunneling microscopy (VT-STM). The THB behaviors in the UHV system are similar to those under ambient conditions, except that the average hole diameter becomes larger, which is attributed to fewer conduction paths of heat energy in the UHV system. As the specimen temperatures are reduced, the threshold voltage of hole formation increases and the volumes of the holes become smaller. The existence of such temperature dependence suggests that the hole formation is closely related to a STM current-induced localized heating effect. We also estimate the temperature rise and analyze the thermal gravity and mass spectroscopy (TG-MS) for detailed understanding of the thermochemical decomposition reaction.