The electrical behavior of Pt/TiO2/NSTO/Pt structures fabricated by plasma-assisted molecular beam epitaxy has been investigated. And it is found that the interface states have impact on the electrical resistance. The structures' resistance could be changed by voltage pulses of 1 ms width in the way of capture and release of electrons at the interface. The negative differential resistance in backward bias regions could be ascribed to the progressive release of trapped electrons. The electrical tests demonstrate that interface states distribute within the band gap. The different resistance state could derive from the amount and specified release of trapped electrons. Additionally, the structure's resistance tends to come to a certain value after the electrical stimulation in a few days. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3586241] All rights reserved.