Juras Banys - Van der Waals Ferroelectrics: Properties and Device Applications of Phosphorous Chalcogenides

1. Chapter 1
2. Chapter 2
3. Chapter 3
4. Chapter 4
5. Chapter 5
6. Chapter 6
7. Chapter 7
8. Chapter 9
9. Chapter 10

1. Chapter 1
2. Chapter 2
3. Chapter 3
4. Chapter 4
5. Chapter 5
6. Chapter 6
7. Chapter 7
8. Chapter 8
9. Chapter 9
10. Chapter 10

Juras Banys

Andrius Dziaugys

Konstantin E. Glukhov

Anna N. Morozovska

Nicholas V. Morozovsky

Yulian M. Vysochanskii

Authors

Prof. Juras Banys

Vilnius University, Faculty of Physics

Institute of Applied Electrodynamics

and Telecommunications

Saultekio av. 9, III bld

10222 Vilnius

Lithuania

Dr. Andrius Dziaugys

Vilnius University, Faculty of Physics

Institute of Applied Electrodynamics

and Telecommunications

Saultekio av. 9, III bld

10222 Vilnius

Lithuania

Dr. Konstantin E. Glukhov

Uzhgorod National University

Institute Physics & Chemistry of Solid State

54 Voloshin Street

88000 Uzhgorod

Ukraine

Dr. Anna N. Morozovska

National Academy of Sciences of Ukraine

Institute of Physics

46, pr. Nauky

03028 Kyiv

Ukraine

Dr. Nicholas V. Morozovsky

National Academy of Sciences of Ukraine

Institute of Physics

46, pr. Nauky

03028 Kyiv

Ukraine

Prof. Yulian M. Vysochanskii

Uzhgorod National University

Institute Physics & Chemistry of Solid State

54 Voloshin Street

88000 Uzhgorod

Ukraine

Cover Image: Science History Images/Alamy Stock Photo

All books published by WILEYVCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.:

applied for

British Library CataloguinginPublication Data

A catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche Nationalbibliothek

The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at .

2022 WILEYVCH GmbH, Boschstrae 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form by photoprinting, microfilm, or any other means nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 9783527350346

ePDF ISBN: 9783527837151

ePub ISBN: 9783527837168

oBook ISBN: 9783527837175

After the discovery of graphene and its intriguing features, scientists have become increasingly interested in twodimensional ( 2D ) crystals with strong inplane covalent bonds and weak van der Waals ( vdW ) interlayer interactions. The simplicity and rapid prototyping of micromechanical exfoliation technique, combined with a wide range of properties covered by these materials, have opened up a vast study field with the potential to impact a wide range of applications. The absence of a natural energy bandgap, on the other hand, limits the usefulness of graphene for highperformance electrical switches and other optoelectronic devices. Here, alternative 2D materials, such as transition metal chalcogenophosphate s ( TMCP s), can play an essential role in this application. Natural bandgaps in these materials allow investigators to expand the scope of their research. TMCPs of the general formula MPX3 (M is transition metal or combination of metals: CuIn, AgIn, CuBi, CuCr, and AgCr, P is phosphorus and X = S or Se chalcogens) have stimulated the interest of the 2D material science community because they have multiferroic properties, making them easy to exfoliate with cleavage energies even lower than in graphite. The pursuit of longrange ferroic ordering in vdW materials, such as ferroelectricity, ferromagnetism, and ferroelasticity, is on the rise with the fast development of vdW materials. Ferroelectricity is one of them, with applications in memory, capacitors, actuators, and sensors being researched extensively. The spontaneous ordering of electric dipoles below the Curie temperature (Tc) creates macroscopic polarization that may be changed by an external electric field. In condensed matter physics, vdW layered ferroelectric materials have emerged as a potential study area. Furthermore, their outofplane polarization is more suitable for nonvolatile memory and heterostructurebased nanoelectronics/optoelectronics. CuInP2S6 (CIPS) is one of the most representative materials because of its room temperature ferroelectricity. CIPS is formed out of 2D flakes and is a strong piezoelectric material. The height of the flakes can be easily changed using the scotchtape method like for graphene. It is determined that these crystals have the largest nonlinear elastic properties and a large tense resistance. CuInP2S6 is only one known room temperature 2D semiconductor ferroelectric. The vdW gap is around 8A, and it is compatible with modern nanotechnology. The presence of Cr, Bi, and Mn in the lattice allows the occurrence of magnetism (multiferroic). Cu+ is responsible for a high ionic conductivity in CIPS. The high ionic conductivity makes CIPS an ideal system to study the interplay with ferroelectricity. These materials are photosensitive semiconductors with a bandgap width of 0.33eV. Besides, they are also characterized by a strong piezoeffect. CuInP2S6 layered crystals have the largest elastic nonlinearity of the known materials, which is important for acoustoelectronic and signal processing devices. Because of the electrostriction, the piezoeffect can be created by the constant external electric field, which is very important for the development of controllable electroacoustic transducers.

The density functional theory ( DFT ) is used for the ab initio simulation of electron and phonon subsystems of the considered family of layered compounds. A detailed description of spatial charge distribution elucidates the features of complex chemical bonding in both the tightly connected layers and between them. Special attention is paid to the interplay between the orbitals of [P2X6]4+ anion complex and different cations. Estimations of the energetics of dipole or/and spinordered states in materials under study allow explaining the peculiarities of the phase transitions in these structures, including the semiconductorpolar metal transition. Stability of different phases, patterns of atom displacements, phonon frequencies, and estimations of Raman intensities are obtained from the ab initio modeling of the lattice subsystem of a wide variety of representatives of the considered crystal family.