Ultralow-Barrier Antiferroelectric-Ferroelectric Transition Enabled by Competing Polar Distortion in Two-Dimensional Ruddlesden-Popper Nitride Perovskites.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41951569.
- Also identified by DOI 10.1021/acs.nanolett.6c00448 and PMC identifier 13107449.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Two-dimensional Ruddlesden-Popper (2D RP) nitride perovskites, combining strong covalency with reduced dimensionality and weak interlayer coupling, are promising candidates for low-energy polarization control. Here, we study 2D RP nitride perovskite La<sub>2</sub>WN<sub>4</sub> using first-principles calculations in combination with symmetry analysis and mode decomposition. La<sub>2</sub>WN<sub>4</sub> hosts a competing semiconducting ferroelectric (FE, <i>Aba</i>2) phase and antiferroelectric (AFE, <i>Pna</i>2<sub>1</sub>) phase, where polarization originates from WN<sub>6</sub> octahedral distortions coupled to nitrogen displacements. Both the AFE-FE interconversion and polarization reversal proceed over low barriers, enabling fast, energy-efficient switching. External stimuli provide effective control, given that 1% biaxial compressive strain or an in-plane electric field of 0.025 V/Å can reversibly toggle between AFE and FE states. Moreover, La<sub>2</sub>WN<sub>4</sub> can be exfoliated into a stable semiconducting monolayer that retains sizable in-plane polarization with a low switching barrier, highlighting its potential for low-power-programmable AFE/FE functionalities.