Large Family of Two-Dimensional Ferroelectric Metals Discovered via Machine Learning

Abstract

Ferroelectricity and metallicity are usually believed not to coexist because conducting electrons would screen out static internal electric fields. In 1965, Anderson and Blount proposed the concept of 'ferroelectric metal', however, it is only until recently that very rare ferroelectric metals were reported. Here, by combining high-throughput ab initio calculations and data-driven machine learning method with new electronic orbital based descriptors, we systematically investigated a large family (2,964) of two-dimensional (2D) bimetal phosphates, and discovered 60 stable ferroelectrics with out-of-plane polarization, including 16 ferroelectric metals and 44 ferroelectric semiconductors that contain seven multiferroics. The ferroelectricity origins from spontaneous symmetry breaking induced by the opposite displacements of bimetal atoms, and the full-d-orbital coinage metal elements cause larger displacements and polarization than other elements. For 2D ferroelectric metals, the odd electrons per unit cell without spin polarization may lead to a half-filled energy band around Fermi level and is responsible for the metallicity. It is revealed that the conducting electrons mainly move on a single-side surface of the 2D layer, while both the ionic and electric contributions to polarization come from the other side and are vertical to the above layer, thereby causing the coexistence of metallicity and ferroelectricity. Van der Waals heterostructures based on ferroelectric metals may enable the change of Schottky barrier height or the Schottky-Ohmic contact type and induce a dramatic change of their vertical transport properties. Our work greatly expands the family of 2D ferroelectric metals and will spur further exploration of 2D ferroelectric metals.

arXiv comment28 pages, 5 figures, 1 table

References in corpus (20)

• Electric Field Effect in Atomically Thin Carbon Films
• Atomically thin MoS2: A new direct-gap semiconductor
• Phosphorene: A New 2D Material with High Carrier Mobility
• Physics of thin-film ferroelectric oxides
• The Computational 2D Materials Database: High-Throughput Modeling and Discovery of Atomically Thin Crystals
• Two-dimensional transition metal dichalcogenides under electron irradiation: defect production and doping
• Giant Electroresistance in Ferroelectric Tunnel Junctions
• Robust Ferroelectricity in Monolayer Group-IV Monochalcogenides
• A ferroelectric-like structural transition in a metal
• Berry curvature memory through electrically driven stacking transitions
• Two-Dimensional Multiferroic Semiconductors with Coexisting Ferroelectricity and Ferromagnetism
• Two-Dimensional Hyperferroelectric Metals: a Different Route to Ferromagnetic-Ferroelectric Multiferroics
• Strain-Induced Room-Temperature Ferromagnetic Semiconductors with Large Anomalous Hall Conductivity in Two-Dimensional Cr2Ge2Se6
• Quantum Nonlinear Ferroic Optical Hall Effect
• Ferroelectric nonlinear anomalous Hall effect in few-layer WTe${}_2$
• Tunable ferroelectricity and anisotropic electric transport in monolayer $\beta$-GeSe
• Two-Dimensional Room Temperature Ferromagnetic Semiconductors with Quantum Anomalous Hall Effect
• Critical enhancement of thermopower in a chemically tuned polar semimetal MoTe${}_2$
• Prediction of a native ferroelectric metal
• Accelerated Discovery of Two-Dimensional Optoelectronic Octahedral Oxyhalides via High-Throughput Ab Initio Calculations and Machine Learning

Cited by in corpus (9)

• Two-dimensional ferroelectrics from high throughput computational screening
• Two-dimensional Topological Ferroelectric Metal with Giant Shift Current
• Ferroelectric metals in 1T/1T'-phase transition metal dichalcogenide MTe2 bilayers (M = Pt, Pd, and Ni)
• Interface engineering of ferroelectricity in thin films of thiophosphate ABP 2 X 6 (A = Cu, Ag; B = In, Bi, Cr, V; and X = S, Se)
• High-Efficient ab initio Bayesian Active Learning Method and Applications in Prediction of Two-dimensional Functional Materials
• Voting Data-Driven Regression Learning for Discovery of Functional Materials and Applications to Two-Dimensional Ferroelectric Materials
• Ferroelectric topological superconductor
• Combining intrinsic and sliding-induced polarizations for multistates in two dimensional ferroelectrics
• Controllable spin splitting in 2D Ferroelectric few-layer ${$γ}$-GeSe