Piezoelectric and pyroelectric properties of (001) oriented KNbO3 film

Qiu, Jianhua; Zhao, Tong; Chen, Z.H.; Wang, X.Q.; Yuan, Ningyi; Ding, Jianning

doi:10.1016/j.ssc.2018.09.002

Cited by 6 publications

(8 citation statements)

References 21 publications

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“…As pristine tetragonal KNbO 3 is not the thermodynamically stable phase at room temperature, experimental data on the pyroelectric effect are scarce. Qiu et al have recently used phenomenological Landau–Devonshire theory to investigate the γ-phase of a (001)-oriented KNbO 3 film . Their model shows reasonable agreement with experimental data on remanent polarization and piezoelectric coefficient.…”

Section: Resultsmentioning

confidence: 91%

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Eklund,

Karttunen

2023

J. Phys. Chem. C

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We present a computational methodology for investigating the pyroelectric properties of anharmonic crystalline ferroelectrics. The description of phonon properties and pyroelectricity in perovskite ferroelectrics such as BaTiO3 and KNbO3 requires phonon anharmonicity to be taken into account. Our computational approach is based on density functional theory calculations. We use self-consistent phonon theory to describe phonon anharmonicity and to obtain finite-temperature atomic displacements. The Berry phase approach is used to obtain spontaneous polarization needed for the prediction of the primary pyroelectric coefficient. We calculate the fixed-volume primary pyroelectric coefficient and piezoelectric strain secondary pyroelectric coefficient for the tetragonal polymorphs of BaTiO3 and KNbO3. We also report the anharmonic phonon dispersions for the studied systems. The computationally relatively straightforward and cost-efficient approach offers a way of screening the pyroelectric coefficients of novel pyroelectric materials for energy harvesting and other microelectronic applications.

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Section: Resultsmentioning

confidence: 91%

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Eklund,

Karttunen

2023

J. Phys. Chem. C

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“…Next, we further study the effect of epitaxial strain on the NC starting from a simple thermodynamic Landau model − (details in the Supporting Information) to understand the mechanism of strain tuning of the NC effect in ferroelectric films. In Landau’s theory, assuming that there is only a uniform polarization along the (101) pc direction in the orthorhombic KNO, the ferroelectric free energy can be written as G = false( α 1 * + α 3 * false) P 1 2 + false( α 11 * + α 33 * + α 13 * false) P 1 4 + false( 2 α 111 + 2 α 112 false) P 1 6 + false( 2 α 1111 + 2 α 1112 + α 1122 false) P 1 8 − E P 1 + ε 2 s 11 + s 22 with α 1 * , α 3 * , α 13 * , α 33 * , α 111 , α 112 ...…”

Section: Resultsmentioning

confidence: 99%

“…Next, we further study the effect of epitaxial strain on the NC starting from a simple thermodynamic Landau model − (details in the Supporting Information) to understand the mechanism of strain tuning of the NC effect in ferroelectric films. In Landau’s theory, assuming that there is only a uniform polarization along the (101) pc direction in the orthorhombic KNO, the ferroelectric free energy can be written as with α 1 * , α 3 * , α 13 * , α 33 * , α 111 , α 112 , α 1111 , α 1112 , and α 1122 , where s 11 and s 22 are the Landau coefficients, E is the applied electric field, and ε is the strain.…”

Section: Resultsmentioning

confidence: 99%

Strain Tuning of Negative Capacitance in Ferroelectric KNbO₃ Thin Films

Luo

Wang

Chen

et al. 2023

ACS Appl. Mater. Interfaces

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Ferroelectrics with negative capacitance effects can amplify the gate voltage in field-effect transistors to achieve low power operation beyond the limits of Boltzmann's Tyranny. The reduction of power consumption depends on the capacitance matching between the ferroelectric layer and gate dielectrics, which can be well controlled by adjusting the negative capacitance effect in ferroelectrics. However, it is a great challenge to experimentally tune the negative capacitance effect. Here, the observation of the tunable negative capacitance effect in ferroelectric KNbO 3 through strain engineering is demonstrated. The magnitude of the voltage reduction and negative slope in polarization-electric field (P−E) curves as the symbol of negative capacitance effects can be controlled by imposing various epitaxial strains. The adjustment of the negative curvature region in the polarization-energy landscape under different strain states is responsible for the tunable negative capacitance. Our work paves the way for fabricating low-power devices and further reducing energy consumption in electronics.

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“…Simulations of strain tunable NC effect in KNO. Next, we further study the effect of epitaxial strain on the NC starting from a simple thermodynamic Landau model [41][42][43] (Details in Supplementary material) to understand the mechanism of strain tuning of NC effect in ferroelectric lms. In Landau's theory, assuming that there is only a uniform polarization along the (101) pc direction in orthorhombic KNO, the ferroelectric free energy can be written as G= (α * 1 + α * 3 )P > 0, thus the free energy-polarization landscape shows double-well characteristic.…”

Section: Resultsmentioning

confidence: 99%

Strain tuning of negative capacitance in ferroelectric KNbO3 thin films

Luo

Chen

Wang

et al. 2022

Preprint

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Ferroelectrics with negative capacitance effect can amplify the gate voltage in field-effect transistors to achieve low power operation beyond the limits of the Boltzmann's Tyranny. The reduction of power consumption depends on the capacitance matching between the ferroelectric layer and gate dielectrics, which can be well controlled by adjusting the negative capacitance effect in the ferroelectrics. However, it is a great challenge to experimentally tune the negative capacitance effect. Here, the observation of tunable negative capacitance effect in ferroelectric KNbO3 through strain engineering is demonstrated. The magnitude of the voltage reduction and negative slope in polarization-electric field (P-E) curves as the symbol of negative capacitance effect can be controlled by imposing various epitaxial compressive strain. The expansion of negative curvature region in polarization-energy landscape under compressive strain is responsible for the tunable negative capacitance. Our work paves the way for fabricating low power devices and further reducing energy consumption in electronics.

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Piezoelectric and pyroelectric properties of (001) oriented KNbO3 film

Cited by 6 publications

References 21 publications

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Strain Tuning of Negative Capacitance in Ferroelectric KNbO₃ Thin Films

Strain tuning of negative capacitance in ferroelectric KNbO3 thin films

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Piezoelectric and pyroelectric properties of (001) oriented KNbO3 film

Cited by 6 publications

References 21 publications

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO3 and KNbO3 Studied with Density Functional Theory

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO3 and KNbO3 Studied with Density Functional Theory

Strain Tuning of Negative Capacitance in Ferroelectric KNbO3 Thin Films

﻿Strain tuning of negative capacitance in ferroelectric KNbO3 thin films

Contact Info

Product

Resources

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Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Strain Tuning of Negative Capacitance in Ferroelectric KNbO₃ Thin Films

Strain tuning of negative capacitance in ferroelectric KNbO3 thin films