Electronic\nand Transport Engineering of A‑Type\nAntiferromagnets with Ferroelectric Sandwich Structure: Toward Multistate\nNonvolatile Memory Applications

Achieving higher-order multistates with mutual interstate\nswitching\nat the nanoscale is essential for high-density storage devices; yet,\nit remains a significant challenge. Here, we demonstrate that integrating\nA-type antiferromagnetic semiconductors sandwiched between ferroelectric\nlayers is an effective strategy to achieve high-performance multistate\ndata storage. Taking the Sc<sub>2</sub>CO<sub>2</sub>/VSi<sub>2</sub>P<sub>4</sub> bilayer (bi-VSi<sub>2</sub>P<sub>4</sub>)/Sc<sub>2</sub>CO<sub>2</sub> van der Waals multiferroic heterostructure as an example,\nour first-principles calculations show that by switching the polarization\ndirection of the upper and bottom ferroelectric Sc<sub>2</sub>CO<sub>2</sub> layers, antiferromagnetic bi-VSi<sub>2</sub>P<sub>4</sub> can exhibit four distinct states with different band structures.\nThe intriguing band structure engineering stems from the polarization-field-induced\nband shift and interface charge transfer. Accordingly, the proposed\nSc<sub>2</sub>CO<sub>2</sub>/bi-VSi<sub>2</sub>P<sub>4</sub>/Sc<sub>2</sub>CO<sub>2</sub>-based multiferroic device can achieve four\ndifferent resistance states, accompanied by fully spin-polarized currents\nand giant tunneling electroresistance ratios. Our results propose\na viable strategy for realizing nonvolatile electrical control of\nantiferromagnets at the nanoscale and provide insights into the development\nof advanced memories.