Fig. 4: Evidence of polarity.
From: Glassy dynamics of SrTiO3-based two-dimensional electron gas
a Sheet carrier density (n1) of the dominant carrier density channel as a function of temperature showing carrier freezing below 150 K. We emphasize that our sample exhibits two-band transport below 90 K, and therefore, n1 at 90 K and above was determined using one band model, whereas below 90 K it corresponds to the dominant carrier density channel obtained from the two band fitting. For more details please see Supplementary Fig. S12. Inset shows Arrhenius plot of ln(n1) versus 1000/T for the temperature range 300–25 K71. The black dotted line shows a linear fit upto 125 K while the red dotted line shows a linear fit between 100 K and 35 K, where majority of trapping happens in domain wall defect states. b Schematic shows the proposed mechanism as the origin of slow relaxation of resistance. For a fixed phonon bath temperature, DW defect states increase with decreasing the effective temperature of the DWs. As a result, the polarity of DWs increases and more and more electrons are getting trapped in DWs from 2DEG. The green arrow indicates that the DWs' DOS is increasing over time. c Temporal evolution of resistance at fixed temperatures of 20 K and 80 K after zero-field cooling and field cooling. The temperature ramping protocol for zero field cooling is similar to Fig. 2a and for field cooling (shown in the inset), the system was cooled down from room temperature in the presence of a back gating voltage (Vg),- 50 V to a fixed temperature \(\left({T}_{{{{{\rm{w}}}}}}\right)\) at which the temporal evolution of resistance is measured. d The relative percentage change of resistance at the end of three hours \(\frac{\delta R(t={{{{\rm{3hrs}}}}})}{{R}_{0}}( \% )\) for several fixed temperatures for zero field cooling (blue circles) and field cooling (red squares).
