Random barrier double-well model for resistive switching in tunnel barriers

Abstract

18 pages, 5 figuresInternational audienceThe resistive switching phenomenon in MgO-based tunnel junctions is attributed to the effect of charged defects inside the barrier. The presence of electron traps in the MgO barrier, that can be filled and emptied, locally modifies the conductance of the barrier and leads to the resistive switching effects. A double-well model for trapped electrons in MgO is introduced to theoretically describe this phenomenon. Including the statistical distribution of potential barrier heights for these traps leads to a power-law dependence of the resistance as a function of time, under a constant bias voltage. This model also predicts a power-law relation of the hysteresis as a function of the voltage sweep frequency. Experimental transport results strongly support this model and in particular confirm the expected power laws dependencies of resistance. They moreover indicate that the exponent of these power laws varies with temperature as theoretically predicted

Taming the resistive switching in Fe/MgO/V/Fe magnetic tunnel junctions: An ab initio study

“…The models that describe the RSw, rely usually on an assumption of two local minima in the energy profile. Recently, a double well model for trapped electrons in MgO-based tunnel junctions [14] confirm the power law dependencies of resistance observed experimentally [15].…”

“…Notice however that experimentally the applied voltage is about 1 volt and since the potential drop will occur only through the insulating region of the order of 1 nm (see Ref. [14]), the produced electric field in MgO is of the order of 10 9 V/m which of about the same order of magnitude than the estimated electric field.…”

Zinc phthalocyanine conjugated cellulose nanocrystals for memory device applications

“…Figure 4(d) shows that the two distinctive conductive states are discernable at a bias of +1.5 V. Occurrence of multi-conductive states at constant bias is known as electrical bi(multi)-stability or as 'switching impact' [40,41]. After withdrawing the stimulation, if the contrast between two states continues for a long time, the device is defined as a 'memory' [42], and if the difference disappears then at that point it may be a threshold [43] type of switching.…”

Localized states in advanced dielectrics from the vantage of spin- and symmetry-polarized tunnelling across MgO

“…However, without knowing of precisely which defect species is responsible for altering magnetotransport in a given MTJ, it is difficult to understand, let alone control, the impact of defects on magnetotransport. This immature state-of-the-art is all the more surprising considering that defects within MgO-based MTJs may be magnetic [29][30][31] , and are thought to underscore advanced device functionalities such as memristive effects 22,32,33 , which may be likened to the operation of a synapse-neuron pathway 34 .…”