Negative capacitance regime in ferroelectrics demystified from nonequilibrium molecular dynamics

Lynch, K. A.; Ponomareva, I.

doi:10.1103/physrevb.102.134101

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…Although the applied field favors the parallel alignment of dipoles, the applied field of 40 kV cm −1 and thermal fluctuations are too small to overcome the energy barrier for homogeneous polarization switching; see Figure . Fast field changes however drive the system out of thermodynamic equilibrium [ 63,64 ] and as soon as the field is applied, up to

4 %

of the dipoles in the negative domain spontaneously align with the field direction. The larger the applied field, the more the dipoles have enough energy to overcome the energy barrier to switch, and we find an increase in the amount of reversed dipoles up to 2% for 20 kV mm −1 , 2.6% for 30 kV mm −1 , and up to 4% for 40 kV mm −1 by initial switching, see also Figure F1a, Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio‐Based Molecular Dynamics Study

Khachaturyan

Dimou

Grünebohm

2022

Physica Rapid Research Ltrs

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Optimizing ferroelectrics for contemporary high‐frequency applications asks for the fundamental understanding of ferroelectric switching and domain wall (DW) motion in ultrafast field pulses while the microscopic understanding of the latter is so far incomplete. To close this gap in knowledge, ab initio‐based molecular dynamics simulations are utilized to analyze the dynamics of 180° DWs in the prototypical ferroelectric material BaTiO3. How ultrafast field application initially excites the dipoles in the system and how they relax to their steady state via transient negative capacitance are discussed. Excitingly, a giant boost of the DW velocity related to the nonequilibrium switching of local dipoles acting as nucleation centers for the wall movement is found. This boost may allow to tune the local ferroelectric switching rate by the shape of an applied field pulse.

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Section: Resultsmentioning

confidence: 99%

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio‐Based Molecular Dynamics Study

Khachaturyan

Dimou

Grünebohm

2022

Physica Rapid Research Ltrs

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“…The negative slope in the P(E) loop without entering the NC region is theoretically investigated on a single FE capacitor by incorporating the depolarization and stray fields due to the multidomain structure [92]. First-principles nonequilibrium molecular dynamics simulations indicate that the negative slope originates from the partial screening of the polarization and is more likely to occur when a significant electric field is applied to the FE layer [93]. By introducing the term internal electric field, Eint, which is the applied electric field, Eapp, subtracting the depolarization field, the negative slope is obtained in the P(Eint) curves but does not appear in the P(Eapp) curves (Fig.…”

Section: Possible Origins Of Steep Ssmentioning

confidence: 99%

Current Prospects and Challenges in Negative-Capacitance Field-Effect Transistors

Islam

Mazumder

Zhou

et al. 2023

IEEE J. Electron Devices Soc.

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For decades, the fundamental driving force behind energy-efficient and cost-effective electronic components has been the downward scaling of electronic devices. However, due to approaching the fundamental limits of silicon-based complementary metal-oxide-semiconductor (CMOS) devices, various emerging materials and device structures are considered alternative aspirants, such as negative-capacitance field-effect transistors (NCFETs), for their promising advantages in terms of scaling, speed, and power consumption. In this article, we present a brief overview of the progress made on NCFETs, including theoretical and experimental approaches, a current understanding of NCFET device physics, possible physical mechanisms for NC, and future functionalization prospects. In addition, in the context of recent findings, critical technological difficulties that must be addressed in the NCFET development are also discussed.

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“…This lack of knowledge becomes increasingly important in the case of ultra-fast field applications which drive the system out of equilibrium [9] and may induce new functional properties. For example, a giant electrocaloric response [35] and a negative coupling between field and polarization [10] including transient negative capacitance (NC) [36,37] have already been reported.…”

Section: Introductionmentioning

confidence: 99%

“…Although being counter-intuitive at the first glance NC could be related to the switching of dipoles against the applied field and has been related to antiparallel local depolarization fields which may overcompensate the applied electric field [9,39]. Indeed NC has already been reported during the nucleation of reversed domains [40] or DW propagation [11,37,41,42]. In spite of the progress in this field, the microscopic picture of NC as well as its impact on DW propagation is not yet well investigated.…”

Section: Introductionmentioning

confidence: 99%

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio-Based Molecular Dynamics Study

Khachaturyan,

Dimou,

Grünebohm

2021

Preprint

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Although being crucial for GHz and THz applications, the ferroelectric response to ultrafast field stimuli is so far not well understood. We utilize ab initio based molecular dynamics simulations to analyze the ultrafast response of 180 • domain walls in the prototypical ferroelectric material BaTiO3. We reveal an initial acceleration of the domain wall up to 200% by non-equilibrium dipole switching and the equilibration to the steady-state by transient negative capacitance. Our detailed analysis reveals that the latter is a result of excess charge formation by switched local dipoles with low correlation. In addition, we suggest a relation between average bound charge and spacial dipoles distribution which can be used for statistical analyses of ferroelectric materials.

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Negative capacitance regime in ferroelectrics demystified from nonequilibrium molecular dynamics

Cited by 5 publications

References 23 publications

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio‐Based Molecular Dynamics Study

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio‐Based Molecular Dynamics Study

Current Prospects and Challenges in Negative-Capacitance Field-Effect Transistors

Domain Wall Acceleration by Ultrafast Field Application: An Ab Initio-Based Molecular Dynamics Study

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