Van der Waals Ferroelectrics Properties and Device Applications of Phosphorous Chalcogenides

Van der Waals Ferroelectrics

A comprehensive guide to a unique class of compounds with a variety of applications

Since the discovery of graphene, there has been intensive interest in two-dimensional materials with similar electronic and industrial applications. The limitations on the usefulness of graphene itself, however, have powered the search for other materials with similar properties. One such class of materials, the phosphorous chalcogenides, has proven a particularly fruitful avenue for research, due to the favorable band gap and ferroelectric properties of these materials.

Van der Waals Ferroelectrics provides, for the first time, a detailed overview of this highly relevant and sought-after class of materials, also known as transition metal chalcogenophosphates (TMCPs). Focusing on physical properties, the book explores the complex physics underlying these compounds as well as the unique characteristics that have driven their ever-increasing importance to the materials science community.

Van der Waals Ferroelectrics readers will also find:

• Both computational and experimental perspectives on TCMP compounds
• In-depth discussion of the properties essential to the design and construction of devices like sensors, actuators, memory chips, and capacitors
• The first detailed review of the functional properties of TCMP compounds, such as ferrielectricity, electrostriction, and ionic conductivity

Van der Waals Ferroelectrics is a useful reference for materials scientists, inorganic chemists, solid state chemists, solid state physicists, electrical engineers, and libraries supporting these professions.

Juras Banys, PhD, is a Professor in the Faculty of Physics at Vilnius University, Lithuania.

Andrius Dziaugys, PhD, is a senior researcher in the Institute of Applied Electrodynamics and Telecommunications at Vilnius University, Lithuania.

Konstantin E. Glukhov, PhD, is a senior researcher in the Department of Physics of Semiconductors at Uzhhorod University, Ukraine.

Anna N. Morozovska, PhD, is a leading scientific researcher in the Department of Physics of Magnetic Phenomena at the Institute of Physics of the National Academy of Science of Ukraine.

Nicholas V. Morozovsky, PhD, is a leading scientific researcher in the Laboratory of Applied Ferroelectricity at the Institute of Physics of the National Academy of Science of Ukraine.

Yulian M. Vysochanskii, PhD, is Professor and Head of the Semiconductor Physics Department at Uzhhorod University, Ukraine.

1 CRYSTAL STRUCTURE AND PHASE TRANSITIONS IN LAYERED CRYSTALS OF TERNARY PHOSPHOROUS CHALCOGENIDES
1.1. Ferrielectric, antiferroelectric and modulated orderings in MM'P2X6 (M-Cu, Ag;
M'-In, Bi;
X'S, Se)
1.2. Relaxor and dipole glassy states on phase diagram of CuInP2(SexS1-x)6 mixed crystal
1.3. Antiferromagnetic ordering and glassy state in multiferroics (Cu1-xCrx)P2S6
1.4. Trigonal to monoclinic phase transition in Cd2P2S6 crystal
1.5. Magnetic ordering in Mn2P2S6 crystal
1.6. Polar layered crystals of SnP2S6 type

2. ELECTRONIC BAND STRUCTURE
2.1. Chemical bonding in P2S(Se)6 structural groups
2.2. Hybridization of electronic valence orbitals and structural stability of MM'P2S(Se)6 type compounds
2.3. Second order Jahn Teller effect and dipole ordering in Cu(Ag)InP2S(Se)6 crystals with d10 Cu+ and Ag+ cations
2.4. Second order Jahn Teller effect and phase transitions in Cu(Ag)BiP2S(Se)6 crystals with stereoactive electronic lone pair of Bi3+

3. OPTICAL PROPERTIES OF MM'P2S(SE)6 CRYSTALS
3.1. DFT calculated electronic band structures and optical parameters
3.2. Temperature dependence of the optical absorption for Mn2P2S6, AgInP2S6, CuInP2S(Se)6, CuCrP2S6, SnP2S6 layered crystals
3.3. Appearance of dipole glassy state in edge optical absorption of CuInP2(SexS1-x)6 mixed crystals

4. PHONON SPECTRA OF LAYERED MM'P2S(SE)6 CRYSTALS
4.1. DFT calculated phonon spectra in different phases
4.2. Raman spectroscopy of CuInP2S6 crystal across ferrielectric phase transition
4.3. Phonon spectra of CuInP2(SexS1-x)6 mixed crystals
4.4. Anisotropy of thermal conductivity temperature dependence in Cu(Ag)In(Bi)P2S(Se)6 layered crystals
4.5. Heat capacity anomalies at dipole and magnetic ordering in CuInP2S(Se)6 and CuCrP2S6 crystals
4.6. Phonon spectra transformation at trigonal-monoclinic phase transition in Cd2P2S6
4.7. Spin-phonon coupling in Mn2P2S6 crystals

5 SEMICONDUCTOR TO METAL TRANSITIONS IN SNP2S6 AND SN2P2S6 TYPE COMPOUNDS.
5.1. Layered GeP2S6, GeP2Se6, GeP2Te6, SnP2S6, SnP2Se6, SnP2Te6 polar crystals with by pressure or chemical composition induced semiconductor-metal transition
5.2. By pressure induced metal state in Sn2P2S6 and Sn2P2Se6 compounds
5.3. DFT calculated transformation of electron and phonon spectra at transition into polar metal state

6. DIELECTRIC AND FERROELECTRIC PROPERTIES OF LAYERED PHOSPHORUS CHALCOGENIDE CRYSTALS
6.1. Anisotropy effects in thick layered CuInP2S6 and CuInP2Se6 crystals
6.2. Inhomogeneous ferrielectrics
6.3. Dipole glass state in Cu(InxCr1-x)P2S6 crystals
6.4. Dielectric studies of two-dimensional CuInP2(SxSe1-x)6 mixed crystals
6.5. Non-linear dielectric response of layered CuInP2S6 and Cu0.9Ag0.1InP2S6 crystals
6.6. Dielectric spectroscopy of CuBiP2Se6 crystals

7. IONIC CONDUCTIVITY AND LOW-FREQUENCY NOISE SPECTROSCOPIC STUDIES
7.1. Ionic conductivity investigations in CuInP2S6 and CuIn1+dP2S6 crystals
7.2. Conductivity spectroscopy of AgInP2(SexS1-x) and (CuxAg1-x)CrP2S6 crystals
7.3. Low-frequency noise spectroscopy of layered CuInP2S6
7.4. Electrical conductivity of layered CuInP2(SxSe1-x)6 crystals

8. ULTRASONIC AND PIEZOELECTRIC STUDIES OF PHASE TRANSITIONS IN TWO DIMENSIONAL CUINP2S6 TYPE CRYSTALS
8.1. Ultrasonic investigation of phase transition in CuInP2S6 Crystals
8.2. Piezoelectric and ultrasonic studies of mixed AgxCu1-xInP2(S,Se)6 layered crystals
8.3. Ultrasonic spectroscopy of quasi two-dimensional CuInP2(SexS1-x)6 mixed crystals.
8.4. Piezoelectric and elastic properties of layered materials of Cu(In,Cr)P2(S,Se)6 system

9. NANO SCALE INVESTIGATIONS, DOMAIN STRUCTURE AND SWITCHING PROCESSES OF LOW-DIMENSIONAL FERROELECTRIC LAYERED CHALCOGENIDES
9.1. Ferrielectric state in several layers or monolayer CuInP2S6 samples.
9.2. Bright domain walls in CuInP2Se6 crystals
9.3. Antisite Defects in Layered Multiferroic CuCr0.9In0.1P2S6

10. PHENOMENOLOGICAL DESCRIPTION OF SOFT PHONON SPECTRA, PHASE DIAGRAMS AND DOMAIN MORPHOLOGY OF LOW-DIMENSIONAL FERROELECTRIC LAYERED CHALCOGENIDES
10.1. Brief overview of existing phenomenological models
10.2. Spatially-modulated incommensurate phases and soft phonon dispersion in ferroelectric layered chalcogenides
10.3. Phase diagrams with incommensurate phases and domain splitting in thin films of ferroelectric layered chalcogenides
10.4. Phenomenological description of complex domain morphology and phase diagrams of ferroelectric layered chalcogenide nanoparticles
10.5. Phenomenological description of bright-contrast and dark-contrast domain walls in ferroelectric-antiferroelectric layered chalcogenides

11. FUNCTIONAL PROPERTIES AND THEIR USAGE FOR APPLICATIONST
11.1. Layered chalcogenide crystals for ultrasonic transducers
11.2. Ferroelectric capacitors and transistors
11.3. Pyroelectric nanogenerator and electrocaloric cooling device