2013/02/01 by Feng Bi, Mengchen Huang, Bi, Feng +13 · 2 citations
Materials Science · Engineering · #Electronic and Structural Properties of Oxides #Semiconductor materials and devices #Ferroelectric and Negative Capacitance Devices
paper · pdf · doi:10.48550/arxiv.1302.0204
LaAlO3/SrTiO3 heterostructures are known to exhibit a sharp, hysteretic metal-insulator transition (MIT) with large enhanced capacitance near depletion. To understand the physical origin of this behavior, the electromechanical response of top-gated LaAlO3/SrTiO3 heterostructures is probed using two simultaneous measurement techniques: piezoforce microscopy (PFM) and capacitance spectroscopy. PFM measurements reveal local variations in the hysteretic response, which is directly correlated with capacitance measurements. The enhanced capacitance at the MIT is linked to charging/discharging dynamics of nanoscale conducting islands, which are revealed through PFM imaging and time-resolved capacitance and piezoresponse measurements.