Multifunctional 2D FETs exploiting incipient ferroelectricity in freestanding SrTiO nanomembranes at sub-ambient temperatures.

Incipient ferroelectricity bridges traditional dielectrics and true ferroelectrics, enabling advanced electronic and memory devices. Firstly, we report incipient ferroelectricity in freestanding SrTiO nanomembranes integrated with monolayer MoS to create multifunctional devices, demonstrating stable ferroelectric order at low temperatures for cryogenic memory devices. Our observation includes ultra-fast polarization switching (~10 ns), low switching voltage (<6 V), over 10 years of nonvolatile retention, 100,000 endurance cycles, and 32 conductance states (5-bit memory) in SrTiO-gated MoS transistors at 15 K and up to 100 K.

Large Spin Polarization from symmetry-breaking Antiferromagnets in Antiferromagnetic Tunnel Junctions.

Efficient detection of the magnetic state is a critical step towards useful antiferromagnet-based spintronic devices. Recently, finite tunneling magnetoresistance (TMR) has been demonstrated in tunnel junctions with antiferromagnetic electrodes, however, these studies have been mostly limited to junctions with two identical antiferromagnet (AFM) electrodes, where the matching of the spin-split Fermi surfaces played critical role. It remains unclear if AFMs can provide a finite net spin polarization, and hence be used as a spin polarizer or detector.

Uncovering Atomic Migrations Behind Magnetic Tunnel Junction Breakdown.

As advances in computing technology increase demand for efficient data storage solutions, spintronic magnetic tunnel junction (MTJ)-based magnetic random-access memory (MRAM) devices emerge as promising alternatives to traditional charge-based memory devices. Successful applications of such spintronic devices necessitate understanding not only their ideal working principles but also their breakdown mechanisms. Employing an in situ electrical biasing system, atomic-resolution scanning transmission electron microscopy (STEM) reveals two distinct breakdown mechanisms.

Hybrid Molecular Beam Epitaxy for Single-Crystalline Oxide Membranes with Binary Oxide Sacrificial Layers.

The advancement in thin-film exfoliation for synthesizing oxide membranes has led to possibilities for creating artificially assembled heterostructures with structurally and chemically incompatible materials. The sacrificial layer method is a promising approach to exfoliate as-grown films from a compatible material system, allowing for their integration with dissimilar materials. Nonetheless, the conventional sacrificial layers often possess an intricate stoichiometry, thereby constraining their practicality and adaptability, particularly when considering techniques such as molecular beam epitaxy (MBE).