Nanoscale imaging and control of resistance switching in VO_2 at room temperature

摘要

We demonstrate controlled local phase switching of a VO_2 film using a biased conducting atomic force microscope tip. After application of an initial, higher "training" voltage, the resistance transition is hysteretic with IV loops converging upon repeated voltage sweep. The threshold V_(set) to initiate the insulator-to-metal transition is on order ～5 V at room temperature, and increases at low temperature. We image large variations in V_(set) from grain to grain. Our imaging technique opens up the possibility for an understanding of the microscopic mechanism of phase transition in VO_2 as well as its potential relevance to solid state devices.