Electric-Field-Assisted Nanostructuring of a Mott Insulator

Here, the first experimental evidence for a strong electromechanical coupling in the Mott insulator GaTa4Se8 that allows highly reproducible nanoscaled writing by means of scanning tunneling microscopy (STM) is reported. The local electric field across the STM junction is observed to have a threshold value above which the clean (100) surface of GaTa4Se8 becomes mechanically instable: at voltage biases >1.1 V, the surface suddenly inflates and comes in contact with the STM tip, resulting in nanometer‐sized craters. The formed pattern can be indestructibly “read” by STM at a lower voltage bias, thus allowing 5 Tdots inch−2 dense writing/reading at room temperature. The discovery of the electromechanical coupling in GaTa4Se8 might give new clues in the understanding of the electric pulse induced resistive switching recently observed in this stoichiometric Mott insulator. Strong electromechanical coupling in the Mott insulator GaTa4Se8 is shown by experimental evidence for the first time; this behavior allows highly reproducible writing on the nanometer scale by means of scanning tunneling microscopy (STM). Above a threshold voltage, the surface inflates and comes in contact with the STM tip (see figure), resulting in nanometer‐sized craters. These patterns can be indestructibly “read” by STM at lower voltage bias thus, allowing a 5 Tdots per square inch dense writing/reading at room temperature.