Giant tunnelling electroresistance in atomic-scale ferroelectric tunnel junctions

Abstract

Ferroelectric tunnel junctions are promising towards high-reliability and low-power non-volatile memories and computing devices. Yet it is challenging to maintain a high tunnelling electroresistance when the ferroelectric layer is thinned down towards atomic scale because of the ferroelectric structural instability and large depolarization field. Here we report ferroelectric tunnel junctions based on samarium-substituted layered bismuth oxide, which can maintain tunnelling electroresistance of 7 × 105 with the samarium-substituted bismuth oxide film down to one nanometer, three orders of magnitude higher than previous reports with such thickness, owing to efficient barrier modulation by the large ferroelectric polarization. These ferroelectric tunnel junctions demonstrate up to 32 resistance states without any write-verify technique, high endurance (over 5 × 109), high linearity of conductance modulation, and long retention time (10 years). Furthermore, tunnelling electroresistance over 109 is achieved in ferroelectric tunnel junctions with 4.6-nanometer samarium-substituted bismuth oxide layer, which is higher than commercial flash memories. The results show high potential towards multi-level and reliable non-volatile memories.

Growth of emergent simple pseudo-binary ferroelectrics and their potential in neuromorphic computing devices

“…remain unexplored in ferroelectric ZrO 2 and ZnMgO. Also, while very recently studied Bi 1− x Sm x O 3 34 meets some performance parameter requirements for a synaptic element, all these performance parameters need to be explored in a substrate compatible with CMOS fabrication processes.…”

“…7(a)). 34 The FeTJ exhibited long retention time (10 years, Fig. 7(b)) and exceptional cycling endurance (10 9 ).…”

“…3. 18–34 Fig. 3 also provides some keywords for the enhancement of P r with moderate coercive field ( E c ) values (1–2 MV cm −1 ), which can induce large memory windows in non-volatile memory devices such as FeFETs for non-destructive readout operations.…”

Active control of Alfvén eigenmodes by external magnetic perturbations with different spatial spectra

“…The spatial spectrum of applied 3D fields can be further optimized to produce this local FI gradient relaxation while increasing the overall FI confinement [39]. This could improve the plasma performance while suppressing AEs, as achieved in KSTAR for ELMs and disruptions [40]. In future burning plasmas, this method to locally modify the phase-space gradients paves the way to suppress the transport associated with AEs, which could be applied to improve the confinement of NBI fast-ions as well as fusion born alphas, while maintaining the same level of pedestal degradation required by ELM suppression.…”