Negative dielectric constant manifested by static electricity

Yan, Han; Zhao, Cindy X.; Wang, Kevin; Deng, Lucy; Huei‐Ming, Matthew; Xu, Gu

doi:10.1063/1.4792064

Cited by 60 publications

(28 citation statements)

References 13 publications

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“…For |q| > 0, this leaves ε(q, ω = 0) a freedom to be negative without violating the causality or destroying the stability of the system [4,5]. If this happens, then the inverse permittivity has zeros in the upper half of the complex ω-plane, making the permittivity itself a non-analytic function.In the three-dimensional world the realizations of such negative static permittivity are scarce and they mostly concern exotic non-crystalline systems [6][7][8][9][10]. In this work we show that, above a critical wave-vector q > q c in the first Brillouin zone, the permittivity ε(q, ω) of the quasi-two-dimensional (Q2D) systems of the monolayer graphene and boron nitride is negative in the static limit.…”

mentioning

confidence: 88%

“…In the three-dimensional world the realizations of such negative static permittivity are scarce and they mostly concern exotic non-crystalline systems [6][7][8][9][10]. In this work we show that, above a critical wave-vector q > q c in the first Brillouin zone, the permittivity ε(q, ω) of the quasi-two-dimensional (Q2D) systems of the monolayer graphene and boron nitride is negative in the static limit.…”

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confidence: 88%

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Negative static permittivity and violation of Kramers-Kronig relations in quasi-two-dimensional crystals

Nazarov

2015

Phys. Rev. B

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We investigate the wave-vector and frequency-dependent screening of the electric field in atomically thin (quasi-two-dimensional) crystals. For graphene and hexagonal boron nitride we find that, above a critical wave-vector qc, the static permittivity ε(q > qc, ω = 0) becomes negative and the Kramers-Kronig relations do not hold for ε(q > qc, ω). Thus, in quasi-two-dimensional crystals, we reveal the physical confirmation of a proposition put forward decades ago (Kirzhnits, 1976), allowing for the breakdown of Kramers-Kronig relations and for the negative static permittivity. In the vicinity of the critical wave-vector, we find a giant growth of the permittivity. Our results, obtained in the ab initio calculations using both the random-phase approximation and the adiabatic time-dependent local-density approximation, and further confirmed with a simple slab model, allow us to argue that the above properties, being exceptional in the three-dimensional case, are common to quasi-two-dimensional systems. The concept of causality plays one of the central roles in contemporary science [1]. It is well known that causality in the time-domain (the impossibility for an effect to precede the cause in time) leads to the analyticity of a causal response-function in a complex half-plane in the frequency-domain, which, in turn, leads to KramersKronig (KK) relations between the real and the imaginary parts of the response function [2].It must be, however, recognized that the causality assumes that the response-function is applied to a cause and it produces an effect. In the case of the longitudinal electric field in a translationally invarient or a periodic system, the definition of the permittivity ε(q, ω) reads φ tot (q, ω) = φ ext (q, ω)/ε(q, ω), where φ ext and φ tot are the scalar potentials of the externally applied and the total electric fields, respectively. Since the cause is φ ext and the effect is φ tot , not vice versa, this is 1/ε that is guaranteed to be causal, but not ε itself [3]. Accordingly, KK relations must be satisfied by 1/ε, but may or may not be satisfied by ε. For |q| > 0, this leaves ε(q, ω = 0) a freedom to be negative without violating the causality or destroying the stability of the system [4,5]. If this happens, then the inverse permittivity has zeros in the upper half of the complex ω-plane, making the permittivity itself a non-analytic function.In the three-dimensional world the realizations of such negative static permittivity are scarce and they mostly concern exotic non-crystalline systems [6][7][8][9][10]. In this work we show that, above a critical wave-vector q > q c in the first Brillouin zone, the permittivity ε(q, ω) of the quasi-two-dimensional (Q2D) systems of the monolayer graphene and boron nitride is negative in the static limit. Accordingly, KK relations for the permittivity do not hold in this case. The inverse permittivity, on the contrary, remains causal and does satisfy KK relations.We start by writing the permittivity of a Q2D crystal [11] (atomic units e 2 = = m e = 1 are use...

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confidence: 88%

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confidence: 88%

Negative static permittivity and violation of Kramers-Kronig relations in quasi-two-dimensional crystals

Nazarov

2015

Phys. Rev. B

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“…If the imaginary part is positive the effective terminal behavior is capacitive and if it is negative the effective terminal effect is inductive. [6][7][8][9][10][11] In recent years, some researchers have reported a negative capacitance (NC) [6][7][8][9][10][11][12][13] or negative dielectric constant (NDC) [14][15][16] in the forward bias C-V characteristics in some devices. The observation of NDC and NC are important because they imply that an increment of bias voltage produces a decrease in the charge on the electrodes.…”

Section: Introductionmentioning

confidence: 99%

On the frequency dependent negative dielectric constant behavior in Al/Co-doped (PVC+TCNQ)/p-Si structures

Yücedağ

Kaya

Altındal

2014

Int. J. Mod. Phys. B

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The dielectric properties, electric modulus and ac electrical conductivity (σac) of Al/Codoped (PVC + TCNQ)/p-Si structures have been investigated in the wide frequency and voltage range of 0.5 kHz-3 MHz and (−4 V)-(9 V), respectively, using the capacitancevoltage (C-V ) and conductance-voltage (G/ω-V ) measurements at room temperature. The real and imaginary parts of dielectric constant (ε ′ , ε ′′ ), loss tangent (tan δ), σac and the real and imaginary parts of electric modulus (M ′ , M ′′ ) were found strongly function of frequency and applied voltage especially at low frequencies. The ε ′ -V plot shows an anomalous peak in the forward bias region due to the series resistance (Rs), surface states (Nss) and interfacial layer (PVC + TCNQ) effects for each frequency and then it goes to negative values known as negative dielectric constant (NDC) at low frequencies (f ≤ 70 kHz). Such observation of NDC is important result because it implies that an increment of bias voltage produces a decrease in the charge on the electrodes. The amount of negativity ε ′ value increases with decreasing frequency and this decrement in the NDC corresponds to the increment in the ε ′′ .

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“…Such materials may exist and are stable [15]. At the moment, there are only a few papers that present the results of testing materials with a negative value of dielectric constant [16][17][18][19][20][21]. The mechanism that causes the negative value of the dielectric constant has not been fully understood and explained yet.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and dielectric properties of BF–PFN ceramics with negative dielectric loss

Bartkowska

Bochenek

2018

J Mater Sci: Mater Electron

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Multiferroics with negative value of dielectric constant are very promising materials because of their modern applicability. These materials can be used as materials for the construction of electromagnetic radiation shields. The subject of the research is multiferroic BiFeO 3-PbFe 1/2 Nb 1/2 O 3 (BF-PFN) ceramics. For all multiferroic materials the following studies are conducted: SEM, EDS and the temperature dependence of dielectric constant ε′(T). Above a certain temperature (different for different chemical compositions) the value of dielectric constant reaches negative values. Such the behavior of the dielectric constant may indicate that the polarization inside the material has a reverse direction to the external electric field. That is, the electric field inside the material counteracts the applied external electric field. The obtaining materials also show negative dielectric losses. The Axelrod model is used to explain the mechanism that causes negative dielectric loss.

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Negative dielectric constant manifested by static electricity

Cited by 60 publications

References 13 publications

Negative static permittivity and violation of Kramers-Kronig relations in quasi-two-dimensional crystals

Negative static permittivity and violation of Kramers-Kronig relations in quasi-two-dimensional crystals

On the frequency dependent negative dielectric constant behavior in Al/Co-doped (PVC+TCNQ)/p-Si structures

Microstructure and dielectric properties of BF–PFN ceramics with negative dielectric loss

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