Deviation from universal dielectric response in CaCu3Ti4O12

Zaiyuan Zhang,Jinsong Zhu,Yongqiang Li,Kai Chen,Cai Chen,Hongbin Xing,Zhichao Chen,Junming Liu,Ying Wang

doi:10.1063/5.0046351

Zaiyuan Zhang, Jinsong Zhu + Show 7 more

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https://doi.org/10.1063/5.0046351

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Abstract

Giant-permittivity CaCu3Ti4O12 has been modeled by nature at an atomic or electronic scale. Notably, the relation between the imaginary part of the complex dielectric value and the frequency of the applied A.C. electric field is found to deviate from the universal dielectric response in the frame of classic mechanics. Only the deviation is elucidated based on the model, and thus, a clue to quantum dielectric physics appears.

Highlights

As one of the typical giant-permittivity dielectric materials in the last two decades, CaCu3Ti4O12 (CCTO) has hitherto been intensely and widely studied.1–8 It is well established that the inversion-symmetry system consists of polaron-like 3d electrons from B-site Cu2+ ions and onedimensional, antiparallel, and mutually independent dipole chains of A-site specific Ti4+ ions (DPCs).9 Such a dielectric composite of binary dielectric polarizing species is evidenced by the known structural, dielectric, electrical, antiferromagnetic, optical, and photorelated phenomena.9,10 there is some basic physics confusion, even misleading the applications
CaCu3Ti4O12 shows giant temperature- and frequency-independent permittivity and dielectric relaxation with a 100-fold permittivity drop, which is within the frame of a unified physics system that two polarizing species can coexist
The relation between the imaginary part of the complex dielectric value and the frequency of the applied A.C. electric field is beyond the range of the universal dielectric response

Summary

Introduction

As one of the typical giant-permittivity dielectric materials in the last two decades, CaCu3Ti4O12 (CCTO) has hitherto been intensely and widely studied. It is well established that the inversion-symmetry system consists of polaron-like 3d electrons from B-site Cu2+ ions (charged quasiparticles, CQPs) and onedimensional, antiparallel, and mutually independent dipole chains of A-site specific Ti4+ ions (DPCs). Such a dielectric composite of binary dielectric polarizing species is evidenced by the known structural, dielectric, electrical, antiferromagnetic, optical, and photorelated phenomena. there is some basic physics confusion, even misleading the applications. It is well established that the inversion-symmetry system consists of polaron-like 3d electrons from B-site Cu2+ ions (charged quasiparticles, CQPs) and onedimensional, antiparallel, and mutually independent dipole chains of A-site specific Ti4+ ions (DPCs).. It is well established that the inversion-symmetry system consists of polaron-like 3d electrons from B-site Cu2+ ions (charged quasiparticles, CQPs) and onedimensional, antiparallel, and mutually independent dipole chains of A-site specific Ti4+ ions (DPCs).9 Such a dielectric composite of binary dielectric polarizing species is evidenced by the known structural, dielectric, electrical, antiferromagnetic, optical, and photorelated phenomena.. The bandgap value is not a reliable criterion for judging insulators, and as a counterexample, the diamond semiconductor shows a bandgap value of ∼5 eV, which used to be considered as that of the insulator. To further clarify the confusion for applications, it is imperative to compare its response with the universal dielectric one

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