Many-body ab initio diffusion quantum Monte Carlo applied to the strongly correlated oxide NiO.

J Chem Phys

Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.

Published: October 2015

AI Article Synopsis

  • The study uses many-body diffusion quantum Monte Carlo (DMC) methods to investigate the properties of NiO, achieving high accuracy in measurements of lattice constant, cohesive energy, and bulk modulus compared to experimental values.
  • It calculates the quasiparticle bandgap of NiO to be 4.72 eV, closely matching the experimental value of 4.3 eV, and finds a flat upper valence band that aligns with results from Angle Resolved Photoemission Spectroscopy.
  • The research also evaluates the formation energies for oxygen and nickel vacancies, finding that NiO primarily exhibits a p-type character with Ni vacancies being the main intrinsic defects.

Article Abstract

We present a many-body diffusion quantum Monte Carlo (DMC) study of the bulk and defect properties of NiO. We find excellent agreement with experimental values, within 0.3%, 0.6%, and 3.5% for the lattice constant, cohesive energy, and bulk modulus, respectively. The quasiparticle bandgap was also computed, and the DMC result of 4.72 (0.17) eV compares well with the experimental value of 4.3 eV. Furthermore, DMC calculations of excited states at the L, Z, and the gamma point of the Brillouin zone reveal a flat upper valence band for NiO, in good agreement with Angle Resolved Photoemission Spectroscopy results. To study defect properties, we evaluated the formation energies of the neutral and charged vacancies of oxygen and nickel in NiO. A formation energy of 7.2 (0.15) eV was found for the oxygen vacancy under oxygen rich conditions. For the Ni vacancy, we obtained a formation energy of 3.2 (0.15) eV under Ni rich conditions. These results confirm that NiO occurs as a p-type material with the dominant intrinsic vacancy defect being Ni vacancy.

Download full-text PDF

Source
http://dx.doi.org/10.1063/1.4934262DOI Listing

Publication Analysis

Top Keywords

diffusion quantum
8
quantum monte
8
monte carlo
8
defect properties
8
formation energy
8
energy 015
8
rich conditions
8
nio
5
many-body initio
4
initio diffusion
4

Similar Publications

Observation of quantum oscillations near the Mott-Ioffe-Regel limit in CaAs.

Natl Sci Rev

December 2024

State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China.

The Mott-Ioffe-Regel limit sets the lower bound of the carrier mean free path for coherent quasiparticle transport. Metallicity beyond this limit is of great interest because it is often closely related to quantum criticality and unconventional superconductivity. Progress along this direction mainly focuses on the strange-metal behaviors originating from the evolution of the quasiparticle scattering rate, such as linear-in-temperature resistivity, while the quasiparticle coherence phenomena in this regime are much less explored due to the short mean free path at the diffusive bound.

View Article and Find Full Text PDF

A novel particle size distribution correction method based on image processing and deep learning for coal quality analysis using NIRS-XRF.

Talanta

December 2024

State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.

The combined application of near-infrared spectroscopy (NIRS) and X-ray fluorescence spectroscopy (XRF) has achieved remarkable results in coal quality analysis by leveraging NIRS's sensitivity to organic compounds and XRF's reliability for inorganic composition. However, variations in particle size distribution negatively affect the diffuse reflectance of NIRS and the fluorescence signal intensities of XRF, leading to decreased accuracy and repeatability in predictions. To address this issue, this study innovatively proposes a particle size correction method that integrates image processing and deep learning.

View Article and Find Full Text PDF

Imaging of cardiac amyloidosis using dynamic F-FPYBF-2 positron emission tomography.

Ann Nucl Med

December 2024

Clinical Research Center, Shiga General Hospital, 5-4-30, Moriyama-Cho, Moriyama, Shiga, 524-8524, Japan.

Purpose: This study aimed to evaluate the diagnostic ability of 5-(5-(2-(2-(2-F-fluoroethoxy) ethoxy) ethoxy) benzofuran-2-yl)-N-methylpyridin-2-amine (F-FPYBF-2) dynamic PET for patients with cardiac amyloidosis (CA).

Methods: The subjects were patients diagnosed with proven amyloidosis (n = 16) including transthyretin cardiac amyloidosis (ATTR-CA) (n = 7) and light chain amyloidosis (AL amyloidosis) (n = 9), of which 4 and 5 with (AL-CA) and without (AL-nCA) cardiac involvement, and 4 control subjects suffering from some symptoms of cardiac failure without amyloidosis (CTL). Thirty minutes dynamic F-FPYBF-2 PET/CT was performed to evaluate the time activity curve and the retention index (mRI) as the ratio of the myocardial SUV at 15 to 5 min.

View Article and Find Full Text PDF

Thin film photodiodes (TFPD) can supplement complementary metal-oxide-semiconductor (CMOS) image sensor vision by their exotic optoelectronic properties assisted by their monolithic processability. Halide perovskites are known to show outstanding optoelectronic properties, such as large absorption coefficient, long carrier diffusion lengths, and high carrier mobility, leading to high external quantum efficiency (EQE) and fast charge transport in photodiodes (PDs), especially compared with other thin-film photodiode candidates. In this paper, high-resolution two-dimensional (2D) and three-dimensional (3D) imaging capabilities are demonstrated using perovskite photodetection material with a silicon (Si) read-out integrated circuit (ROIC).

View Article and Find Full Text PDF

Well-posedness of Keller-Segel systems on compact metric graphs.

J Evol Equ

December 2024

Department of Mathematics and Statistics, Auburn University, Auburn, AL  36849 USA.

Chemotaxis phenomena govern the directed movement of microorganisms in response to chemical stimuli. In this paper, we investigate two Keller-Segel systems of reaction-advection-diffusion equations modeling chemotaxis on thin networks. The distinction between two systems is driven by the rate of diffusion of the chemo-attractant.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!