Identification of Two-Dimensional Layered Dielectrics from First Principles

2021 ◽  
Author(s):  
Mehrdad Rostami Osanloo ◽  
Maarten Van de Put ◽  
Ali Saadat ◽  
William Vandenberghe
Keyword(s):  
First Principles ◽  
Dielectric Response ◽  
Gate Dielectrics ◽  
Oxide Thickness ◽  
Two Dimensional ◽  
Leakage Currents ◽  
Transistor Channel ◽  
Out Of Plane ◽  
Layered Dielectrics ◽  
Optical Dielectric

Abstract Two-dimensional (2D) van der Waals (vdW) materials promise ideal electrostatic control of charge carrier flow in a channel free of surface roughness or defects. To realize this ideal, good vdW dielectrics are needed in addition to the well explored channel materials. We study the dielectric properties of 32 easily exfoliable vdW materials using first principles methods. Specifically, we calculate the static and optical dielectric response of the monolayer and bulk form. In monolayers, we discover a strong out-of-plane response in GeClF (10.99), LaOBr (13.20), LaOCl (55.80) and PbClF (15.17), while the in-plane dielectric response is strong in BiOCl, PbClF, and TlF, ranging from 64.86 to 98.37. To assess their potential as gate dielectrics, we calculate the bandgap and electron affinity, and estimate the leakage current through the dielectric. We discover seven monolayer 2D dielectrics that promise to outperform bulk HfO2: LaOBr, LaOCl, CaHI, SrBrF, SrHBr, SrHI, and TlF with lower leakage currents at a significantly reduced equivalent oxide thickness. Of these, LaOBr and LaOCl are the most promising and our findings motivate the growth and exfoliation of rare-earth oxyhalides for their use as vdW dielectrics on vdW transistor channel materials.

scholarly journals Identification of two-dimensional layered dielectrics from first principles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mehrdad Rostami Osanloo ◽  
Maarten L. Van de Put ◽  
Ali Saadat ◽  
William G. Vandenberghe
Keyword(s):  
Leakage Current ◽  
First Principles ◽  
Gate Dielectrics ◽  
Oxide Thickness ◽  
Dielectric Constants ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Out Of Plane ◽  
Layered Dielectrics ◽  
Optical Dielectric

AbstractTo realize effective van der Waals (vdW) transistors, vdW dielectrics are needed in addition to vdW channel materials. We study the dielectric properties of 32 exfoliable vdW materials using first principles methods. We calculate the static and optical dielectric constants and discover a large out-of-plane permittivity in GeClF, PbClF, LaOBr, and LaOCl, while the in-plane permittivity is high in BiOCl, PbClF, and TlF. To assess their potential as gate dielectrics, we calculate the band gap and electron affinity, and estimate the leakage current through the candidate dielectrics. We discover six monolayer dielectrics that promise to outperform bulk HfO2: HoOI, LaOBr, LaOCl, LaOI, SrI2, and YOBr with low leakage current and low equivalent oxide thickness. Of these, LaOBr and LaOCl are the most promising and our findings motivate the growth and exfoliation of rare-earth oxyhalides for their use as vdW dielectrics.

scholarly journals Dielectric response of BaZrO3/BaTiO3 superlattice

2016 ◽  
Vol 06 (02) ◽  
pp. 1650015 ◽  
Author(s):  
D. Wang ◽  
Z. Jiang
Keyword(s):  
Molecular Dynamic ◽  
First Principles ◽  
Dielectric Response ◽  
Dynamic Approach ◽  
Chemical Ordering ◽  
Out Of Plane

We use the first-principles-based molecular dynamic approach to simulate dipolar dynamics of BaZrO3/BaTiO3 superlattice, and obtain its dielectric response. The dielectric response is decomposed into its compositional, as well as the in-plane and out-of-plane parts, which are then discussed in the context of chemical ordering of Zr/Ti ions. We reveal that, while the in-plane dielectric response of BaZrO3/BaTiO3 superlattice also shows dispersion over probing frequency, it shall not be categorized as relaxor.

Magnetism of elemental two-dimensional metals

2021 ◽  
Vol 9 (13) ◽  
pp. 4554-4561
Author(s):  
Yinti Ren ◽  
Liang Hu ◽  
Yangfan Shao ◽  
Yijian Hu ◽  
Li Huang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coordination Number ◽  
First Principles ◽  
Energy Band ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Out Of Plane ◽  
D Orbitals

The magnetic properties of 45 2D metals are explored using first-principles calculations. Of the 45 2D metals, 18 are found to be magnetic due to a coordination number decrease and the energy band narrowing of the out-of-plane d orbitals.

Out-of-plane dielectric response of the two-dimensional Mott insulators

2001 ◽  
Vol 357-360 ◽  
pp. 96-98 ◽  
Author(s):  
I. Terasaki ◽  
T. Takayanagi ◽  
M. Kogure ◽  
T. Mizuno
Keyword(s):  
Dielectric Response ◽  
Mott Insulators ◽  
Two Dimensional ◽  
Out Of Plane

First-Principles Prediction of Polar Half-Metallicity and Out-of-Plane Piezoelectricity in Two-Dimensional Quintuple Layered Cobalt Selenide

2021 ◽  
Author(s):  
Cheng Tang ◽  
Lei Zhang ◽  
Yalong Jiao ◽  
Chunmei Zhang ◽  
Stefano Sanvito ◽  
...  
Keyword(s):  
First Principles ◽  
Two Dimensional ◽  
Half Metallicity ◽  
Quantum Devices ◽  
Half Metals ◽  
Out Of Plane ◽  
Cobalt Selenide

Polar half-metals, possessing both polarity and half-metallicity, may have potential as media in novel spintronic quantum devices, but they have never been reported in the two-dimensional (2D) form. By combining...

Zr Oxide Based Gate Dielectrics with Equivalent SiO2 Thickness of Less than 1.0 nm and Device Integration with Pt Gate Electrode

2000 ◽  
Vol 611 ◽  
Author(s):  
Yanjun Ma ◽  
Yoshi Ono
Keyword(s):  
Gate Dielectric ◽  
Process Integration ◽  
Gate Dielectrics ◽  
Oxide Thickness ◽  
Cmos Process ◽  
Metal Gate ◽  
Leakage Currents ◽  
Gate Electrodes ◽  
Device Integration ◽  
Dual Metal

ABSTRACTZrO2 films are investigated as an alternative to SiO2 gate dielectric below 1.5nm. A maximum accumulation capacitance ∼35 fF/μm2 with a leakage current of less than 0.1 A/cm2 has been achieved for a 3 nm Zr-O film, suggesting that ZrO2 can be scaled to below an equivalent oxide thickness of 0.5 nm. Al and Si doping is also investigated to reduce leakage currents and to increase the crystallization temperature of the film. Submicron MOSFETs with TiN or Pt gate electrodes have been fabricated with these gate dielectrics with excellent characteristics, demonstrating the feasibility of CMOS process integration. In particular, Pt damascene gate PMOS is shown to have the proper threshold voltage for dual metal gate CMOS application.

First-Principles Evaluation of the Potential of Borophene as a Monolayer Transparent Conductor

2017 ◽  
Author(s):  
Lyudmyla Adamska ◽  
Sridhar Sadasivam ◽  
Jonathan J. Foley ◽  
Pierre Darancet ◽  
Sahar Sharifzadeh
Keyword(s):  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Transparent Electrode ◽  
Visible Range ◽  
Two Dimensional ◽  
Transparent Conductor ◽  
Many Body ◽  
Functional Theory ◽  
Many Body Perturbation Theory

Two-dimensional boron is promising as a tunable monolayer metal for nano-optoelectronics. We study the optoelectronic properties of two likely allotropes of two-dimensional boron using first-principles density functional theory and many-body perturbation theory. We find that both systems are anisotropic metals, with strong energy- and thickness-dependent optical transparency and a weak (<1%) absorbance in the visible range. Additionally, using state-of-the-art methods for the description of the electron-phonon and electron-electron interactions, we show that the electrical conductivity is limited by electron-phonon interactions. Our results indicate that both structures are suitable as a transparent electrode.

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