Bulletin of the American Physical Society
APS March Meeting 2022
Volume 67, Number 3
Monday–Friday, March 14–18, 2022; Chicago
Session A65: 2D Ferroelectrics and MultiferroicsFocus Recordings Available
|
Hide Abstracts |
Sponsoring Units: DMP Chair: Deliang Bao, Vanderbilt University Room: Hyatt Regency Hotel -Grant Park C |
Monday, March 14, 2022 8:00AM - 8:36AM |
A65.00001: Magnetoelectric correlations in multiferroics at the nanoscale Invited Speaker: Manfred Fiebig Magnetoelectric coupling phenomena in multiferroics were initially treated almost exclusively as bulk effects exhibited by homogeneous materials. In recent years, however, attention has moved to the nanoscale. On the one hand, magnetoelectric phase control ultimately happens on the level of the mostly sub-micrometer-sized domains. On the other hand, domain walls, interfaces and thin films are nanoscale objects that have been proving to be the source of intriguing magnetoelectric coupling effects. In my talk, I will therefore explore the fascinating world of magnetoelectric correlations at the nanoscale in a number of examples, the diversity of which is intended to demonstrate the enormous potential of the nanoscale perspective on multiferroics. Among the examples I may discuss are: [1] a seemingly contradictory coexistence of strong local and forbidden global magnetoelectric coupling in multiferroics with separately emerging magnetic and ferroelectric order (type I); [2] conversion of a multiferroic bulk state into a multiferroic domain wall in a non-multiferroic environment; [3] the evolution of the improper ferroelectric state in a type-I multiferroic towards the thin-film limit of a single monolayer; [4] a giant net-polarization enhancement in low-voltage-switchable La-substituted BiFeO3 heterostructures by electric-field training. |
Monday, March 14, 2022 8:36AM - 8:48AM |
A65.00002: Observations of Defects and Disorder in Ferroelectrics to Identify Their Impact on Phase Transition Behavior Albina Y Borisevich, Sabine M Neumayer, Kyle Kelley, Michael A Susner, Michael A McGuire, Nina Balke, Petro Maksymovych, Rama K Vasudevan Local defects play a decisive role in ferroelectric behavior, affecting domain nucleation, domain wall motion, dynamic response,etc. Quantitative scanning transmission electron microscopy is an indispensable tool in studies of defects, revealing local structure and chemistry down to atomic scale. Combination with in-depth functional characterization with scanning probe methods and advanced data analysis approaches helps understand the impact of these changes on global material behavior. In layered ferroelectric Copper Indium Thiophosphate, we observed defects in layer stacking and local variations in layer spacings. K-means clustering analysis identified three distinct cluster types based on local spacing, possibly correlating to three types of ferroelectric behavior predicted in this system [1]. In perovskite BaTiO3 thin films, we were able to connect enhanced electromechanical response and unusual dynamic behavior to the presence of oxygen vacancies, which were identified both by the emergence of short-range ordering and by characteristic impact on electronic structure [2]. We are expanding our studies into 3D thiophosphate ferroelectric Sn2P2S6 with a complex monoclinic structure and defect behavior that is not well understood. Prospects for observations at variable temperatures will also be discussed. |
Monday, March 14, 2022 8:48AM - 9:00AM |
A65.00003: Measurements on electric polarization of 2D crystals of ferroelectric layered transition metal chalcogenides using graphene as charge sensor Shaoqing Ding, Jinyuan Yao, Justin R Rodriguez, Yanglin Zhu, Zhiqiang Mao, Ying Liu 2D crystals of several layered semiconducting transition metal chalcogenides (TMCs) have been reported to be ferroelectric in recent years, based mostly on piezoelectric force microscopy (PFM) measurements. These TMCs may be used as the channel material in a field effect transistor (FET) that may in turn be used as a nonvolatile memory. The determination of certain basic ferroelectric properties of these materials, such as electric polarization, will be required for the successful use of these ferroelectric TMCs for such a purpose. However, these parameters are for the most part yet to be measured. Conventional dielectric or P-E loop measurements are usually not possible because of the large leakage current stemming from the semiconducting nature of the material, especially the TMC under study is atomically thin. We have developed an alternative approach to the problem which involves combining a capacitor and a back gated FET, using high-mobility, monolayer graphene as a sensor for the surface charge induced by an out-of-plane polarization, which can often be reoriented even when the leakage current is large. We will report our results obtained in atomically thin 2D crystals of CuInP2S6 and α-In2Se3. |
Monday, March 14, 2022 9:00AM - 9:12AM |
A65.00004: Microscopic origin of multiferroic behavior in monolayer NiI2 Adolfo O Fumega, Jose Lado A wide variety of two-dimensional (2D) materials displaying different electronic orders have been isolated, providing the basic building blocks for artificial van der Waals heterostructures. Remarkably, purely 2D ferroelectrics [1] and 2D ferromagnets [2] have been successfully isolated in 2018 and 2017, respectively. However, the discovery of a 2D multiferroic had remained elusive until 2021 [3,4]. These recent experiments demonstrate that NiI2 displays a multiferroic behavior, opening up a whole new direction in van der Waals materials. Here I will present a systematic theoretical analysis of the multiferroicity in NiI2 combining ab initio calculations and low-energy models. In particular, I will address the microscopic origin of the multiferroicity in NiI2, and reveal its fine relation with non-collinearity and spin-orbit effects. This analysis will allow us to determine the main ingredients behind the multiferroic behavior of NiI2, providing a starting point to design new 2D multiferroics. |
Monday, March 14, 2022 9:12AM - 9:24AM |
A65.00005: Computational Discovery and Investigation of New Two Dimensional Ferroelectric Materials Joshua A Young, Mo Li, Olamide Omisakin, Hao Mei Two dimensional ferroelectrics (2DFE, monolayer thick materials with a switchable spontaneous electric polarization) have been proposed for ultrathin electronic devices. However, 2DFEs with large out-of-plane polarizations, ideal for such applications, are challenging to find. Recently, Chandrasekaran et al. proposed that the functionalized MXene Sc2CO2 has a metastable state with an out-of-plane electric polarization larger than other common 2DFEs. [1] In this work, we used density functional theory (DFT) calculations to investigate additional M2CX2 materials (M = Sc, Y, La and X = O, F). We found that (1) chemical substitution of Sc with Y and/or O with F can preferentially stabilize the ferroelectric phase as the ground state; (2) such substitution can also be used to tune the polarization and band gap; and (3) these monolayers display large piezoelectric coefficients. We demonstrate how these properties can be continuously tuned by the application of external strain or by alloying to create Sc2xY2(1-x)CO2 monolayers. Furthermore, we show that the surface reactivity of these materials can be controlled by switching the polarization and preferentially adsorb different adsorbates. Finally, we extend this to new families by using a high throughput DFT approach to scan through a database of 2D materials and compute their polarization to find and verify new 2D ferroelectric materials with out-of-plane polarizations. |
Monday, March 14, 2022 9:24AM - 9:36AM |
A65.00006: Ionic control over ferroelectricity in 2D layered van der Waals capacitors Sabine M Neumayer, Mengwei Si, Junkang Li, Pai-Ying Liao, Lei Tao, Andrew O'Hara, Sokrates T Pantelides, Peide (Peter) Ye, Petro Maksymovych, Nina Balke Originating from their intriguing ferroelectric and ionic properties, van der Waals layered CuInP2S6 provides many interesting opportunities for utilization in memory devices and energy applications. Ferroelectric properties of CuInP2S6 comprise electromechanical activity even in ultrathin samples, large electrostrictive coefficients and the existence of four uniaxial polarization states. These polar properties are underpinned by the position of Cu ions. However, those ions are also highly mobile. Here, we demonstrate how ionic conductivity can be leveraged to control the ferroelectric behavior in CuInP2S6 capacitors. Activating ionic currents through tailored direct voltage pulses impacts coercive voltages as well as the switchable polarization in subsequent probing of ferroelectric switching during fast triangular voltage sweeps. Theoretical calculations indicate that the existence of an internal electric field emanating from inhomogeneous Cu distribution leads to the observed modifications of hysteresis loops. Activating ionic currents can even result in a complete deactivation of hysteretic behavior. Notably, hysteretic polarization switching can be fully restored by activating ionic migration in the opposite direction. This phenomenon provides a path to memory devices beyond binary limitation where information can be encoded in three events: (i) switching from positive to negative polarization, (ii) switching from negative to positive polarization and (iii) no switching within the same voltage range. |
Monday, March 14, 2022 9:36AM - 9:48AM |
A65.00007: Electrode Effects on Ultrathin van der Waals Ferroelectric CuInP2S6 Andrew O'Hara, Lei Tao, Sabine M Neumayer, Petro Maksymovych, Nina Balke, Sokrates T Pantelides Out-of-plane polarized ferroelectric materials placed in a capacitive structure provide a foundation for several technological applications. CuInP2S6 (CIPS) is a van der Waals layered ferrielectric with out-of-plane polarization that can be in a low- or high-polarization (LP or HP) state and is also an ionic conductor with both phenomena controlled by the Cu ions. At the ultrathin limit, many ferroelectrics become paraelectric or antiferroelectric due to depolarizing fields. Here, using density-functional-theory calculations, we explore the effects of several prototypical electrodes (Gr, Ni, Cu, Au, and Ag) on the stabilization of the ferroelectric state compared with possible antiferroelectric states. We find that the ferroelectric state with electrodes can be stabilized with fewer layers compared to the contact-free case and that Au and Ag stabilizing ferroelectricity at the bilayer limit. Furthermore, interactions with the Au and Ag electrodes stabilize the HP state in the ultrathin limit. Quantum-molecular-dynamics simulations show that even at the bilayer limit, the system is switchable despite contact doping of the CIPS layers. |
Monday, March 14, 2022 9:48AM - 10:00AM |
A65.00008: Investigation of polarization switching pathways in ferroelectric van der Waals layered CuInP2S6 Daniel Seleznev, Sobhit Singh, John R Bonini, Karin M Rabe, David Vanderbilt CuInP2S6 (CIPS) is a van der Waals (vdW) layered system exhibiting a variety of intriguing properties. Among these properties is the presence of a strain-induced quadruple-well potential for Cu displacements, which features two low-polarization and two high-polarization states, with the latter corresponding to the presence of a second stable Cu position just inside the vdW gap. The mechanism for polarization switching has been experimentally shown to include the possibility of migration of Cu ions across the vdW gap (instead of solely through the layers), but the detailed pathway taken by the Cu ions in doing so remains poorly understood. Using density functional theory calculations, we investigate the various possible low-energy switching paths involving coherent Cu ion motion, and characterize the sequence of Cu coordination environments visited along the path. Finally, we argue that a such a coherent migration of the Cu sublattice from one vdW layer to the next may be regarded as a realization of quantized adiabatic transport. |
Monday, March 14, 2022 10:00AM - 10:12AM |
A65.00009: Using Bragg CDI to Study CsBiNb2O7 Skye Williams1, Jian Shi1, Edwin Fohtung1 1Department of Materials Sciences and Engineering, Rensselaer Polytechnic Institute, Troy, NY Skye Williams Abstract: |
Monday, March 14, 2022 10:12AM - 10:24AM |
A65.00010: Prediction of three-terminal 2D magnetoelectric heterostructure Xin Jin, Andrew O Hara, Yu-Yang Zhang, Shixuan Du, Sokrates T Pantelides Materials possessing both ferromagnetic (FM) and ferroelectric (FE) orderings enable the control of magnetism by electric fields and the reverse, showing broad applications in various functional devices. The key for the cross control of FM and FE orderings is strong magnetoelectric coupling. Here, by using density-functional-theory calculations, we show that magnetoelectric coupling is enhanced significantly in heterostructures that combine polar FM MnSeTe and FE In2Se3 monolayers. The polarity of the MnSeTe enhances the Dzyaloshinskii-Moriya interaction (DMI) and the magnetoelectric coupling with the In2Se3 monolayer. A bilayer MnSeTe/In2Se3 heterostructure exhibits magnetic skyrmions that can be modulated by reversing the polarization of In2Se3 by an applied electric field. We further design a trilayer In2Se3/MnSeTe/In2Se3 heterostructure, in which multiple FE polarization states enable control of the evolution of magnetic skyrmions in MnSeTe in a three-terminal device configuration. The present findings provide a method to achieve strong magnetoelectric coupling in the 2D limit and a new perspective for the design of related spintronics. |
Monday, March 14, 2022 10:24AM - 10:36AM |
A65.00011: First-principles predictions of local charge distribution in few-layer 2D ferroelectrics Gillian Nolan, Edmund Han, Shahriar M Nahid, Arend M van der Zande, Pinshane Y Huang, Andre Schleife The structural stability of 2D materials at the nanoscale makes them particularly exciting for exhibiting the precise atomic rearrangements involved in ferroelectric switching down to the monolayer. Recent works have presented 2D materials such as SnS, In2Se3, and various transition metal dichalcogenides as promising candidates for exhibiting out-of-plane and/or in-plane ferroelectricity. In this work, we present our first-principles, density functional theory (DFT) predictions of the local electronic charge density at interfaces between multi-layered 2D ferroelectric materials. We rely on charge density predictions for uniformly oriented few-layer structures to draw conclusions on the charge density response observed at interfaces in heterogeneously oriented structures. In particular, we analyze the local charge distribution between ferroelectric domains in few-layer indium selenide (In2Se3), a material recently shown to exhibit out of plane ferroelectric switching and monolayer ferroelectricity. We compare these results with experimental measurements. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700