Local Dielectric Property of Cubic, Tetragonal, and Monoclinic Hafnium Oxides

Senami, Masato; Tsuchida, Yasushi; Fukushima, Akinori; Ikeda, Yûji; Tachibana, Akitomo

doi:10.1143/jjap.51.031101

Cited by 11 publications

(14 citation statements)

References 43 publications

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“…The Pca2 1 polymorph is directly correlated to the ferroelectricity [22], which is due to the formation of the non-centrosymmetric polar orthorhombic phase. The displacement of four polarization-related oxygen atoms per unit cell leads to the polarization of the phase.…”

Section: Phasementioning

confidence: 99%

The Role of Zr on Monoclinic and Orthorhombic HfxZryO2 Systems: A First-Principles Study

et al. 2022

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HfO2 shows different polymorphs, including monoclinic and orthorhombic ones, that exhibit singular properties. Moreover, the character of HfO2 is also influenced by the Zr atoms as a doping agent. Here, an extensive study of the monoclinic P21/c and the orthorhombic Pca21 polymorphs of HfO2, Hf0.75Zr0.25O2, and Hf0.5Zr0.5O2 is reported. For all six systems, density functional theory (DFT) methods based on generalized gradient approximations (GGAs) were first used; then the GGA + U method was settled and calibrated to describe the electrical and optical properties of polymorphs and the responses to the oxygen vacancies. Zr had different effects in relation to the polymorph; moreover, the amount of Zr led to important differences in the optical properties of the Pca21 polymorph. Finally, oxygen vacancies were investigated, showing an important modulation of the properties of HfxZryO2 nanostructures. The combined GGA and GGA + U methods adopted in this work generate a reasonable prediction of the physicochemical properties of o- and m-HfxZryO2, identifying the effects of doping phenomena.

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Section: Phasementioning

confidence: 99%

The Role of Zr on Monoclinic and Orthorhombic HfxZryO2 Systems: A First-Principles Study

et al. 2022

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“…We have proposed the analysis by local quantities [18][19][20][21][22][23][24][25][26][27][28][29][30] defined in rigged quantum electrodynamics (RQED) [18,19]. In the present work, we study the Trans.…”

Section: Introductionmentioning

confidence: 99%

A Non-Hermitian Coupled Perturbed Hartree-Fock Method for Complex Potentials and Calculations of Electronic Structures with Electric Currents

Ikeda

Senami

Tachibana

2013

Trans. Mat. Res. Soc. Japan

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Electronic structures with electric currents are considered in order to investigate conductive properties of nanomaterials in detail. For this purpose, complex potentials which represent sources and sinks of electrons are considered. These complex potentials make Hamiltonian non-Hermitian generally, and hence coupled perturbed Hartree-Fock (CPHF) equations for them are required. In this study, self-energies of electrodes are considered so as to describe interactions between electrodes and a channel molecule, and a perturbation Hamiltonian which corresponds to the complex potentials is constructed based on the self-energies. The present CPHF method is discussed for the perturbation Hamiltonian. Benzenedithiol (BDT) and dihydro-benzenedithiol (DHBDT) are analyzed, and local electric current densities are obtained by using the present method. The delocalization effects of electrons appear as the change of the distribution patterns of the current densities. Conductive properties of nanomaterials are investigated in terms of local conductivities defined in rigged quantum electrodynamics. It can be found that the local conductivities around the π bond between C atoms in BDT are much larger than those around the σ bond in DHBDT.

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“…The rotational response is caused by these response properties. In our previous works, these responses are also seen in the results of ߪ ⃡ ୣ୶୲ ‫ݎ(‬ ⃗) or ߝ ‫ݎ(⃡‬ ⃗) of HfO 2 , SiO 2 , and so on (16)(17)(18)22). Therefore, it can be speculated that these characteristics are often seen in microscopic view.…”

Section: Resultsmentioning

confidence: 70%

Analysis of Local Electric Conductive Property for Si Nanowire Models

2013

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Local electric conductive properties of Si nanowire models are investigated by using two local electric conductivity tensors defined in Rigged QED. It is emphasized that one of these local conductivities is defined as the response of electric current to the actual electric field at a specific point and does not have corresponding macroscopic physical quantity. For the analysis of local conductivities, it is found that there are regions which show complicated response of electric current density to electric field, in particular, opposite and rotational ones. It is also found that two local conductivity tensor shows quite different pattern. We also study the effects of impurities by using a model including a O atom, in terms of the local response to electric field.

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Local Dielectric Property of Cubic, Tetragonal, and Monoclinic Hafnium Oxides

Cited by 11 publications

References 43 publications

The Role of Zr on Monoclinic and Orthorhombic HfxZryO2 Systems: A First-Principles Study

The Role of Zr on Monoclinic and Orthorhombic HfxZryO2 Systems: A First-Principles Study

A Non-Hermitian Coupled Perturbed Hartree-Fock Method for Complex Potentials and Calculations of Electronic Structures with Electric Currents

Analysis of Local Electric Conductive Property for Si Nanowire Models

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