skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: First-principles engineering of charged defects for two-dimensional quantum technologies

; ; ; ;
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
SC0012704; AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 1; Journal Issue: 7; Related Information: CHORUS Timestamp: 2017-12-06 09:40:21; Journal ID: ISSN 2475-9953
American Physical Society (APS)
Country of Publication:
United States

Citation Formats

Wu, Feng, Galatas, Andrew, Sundararaman, Ravishankar, Rocca, Dario, and Ping, Yuan. First-principles engineering of charged defects for two-dimensional quantum technologies. United States: N. p., 2017. Web. doi:10.1103/PhysRevMaterials.1.071001.
Wu, Feng, Galatas, Andrew, Sundararaman, Ravishankar, Rocca, Dario, & Ping, Yuan. First-principles engineering of charged defects for two-dimensional quantum technologies. United States. doi:10.1103/PhysRevMaterials.1.071001.
Wu, Feng, Galatas, Andrew, Sundararaman, Ravishankar, Rocca, Dario, and Ping, Yuan. 2017. "First-principles engineering of charged defects for two-dimensional quantum technologies". United States. doi:10.1103/PhysRevMaterials.1.071001.
title = {First-principles engineering of charged defects for two-dimensional quantum technologies},
author = {Wu, Feng and Galatas, Andrew and Sundararaman, Ravishankar and Rocca, Dario and Ping, Yuan},
abstractNote = {},
doi = {10.1103/PhysRevMaterials.1.071001},
journal = {Physical Review Materials},
number = 7,
volume = 1,
place = {United States},
year = 2017,
month =

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 6, 2018
Publisher's Accepted Manuscript

Save / Share:
  • We report a first-principles, local-density-functional (LDA) calculation of the electronic structure of crystalline, three-dimensional (3D) {ital trans}-(CH){sub {ital x}}. For the perfect crystal, we find a broken-symmetry ground state having {ital P}2{sub 1}/{ital a} space-group symmetry, corresponding to {ital in}-phase dimerization on neighboring chains within the unit cell. We show that in this structure the interchain couplings, although weak, lead to an asymmetry between the valence and conduction bands and, more importantly, give 3D character to the electronic band-edge states. We investigate several additional aspects of the electronic structure of the perfect crystal, including self-consistent optimization of the ions inmore » the unit cell, spin polarization and electronic charge densities, interchain electron-phonon interactions, and the density of states. To study intrinsic defects in {ital trans}-(CH){sub {ital x}}, we map our LDA results onto a multi-orbital, tight-binding model; this mapping preserves very accurately all the electronic-structure properties of the full calculation. Using a Koster-Slater Green-function technique, we are able to examine both (shallow) polaronlike and (deep) bipolaronlike lattice distortions corresponding to localized defects. We find that the 3D character of the electronic band-edge states strongly suppresses the formation of the self-trapped, localized defects characteristic of the 1D models, destabilizing polarons and possibly bipolarons as well in perfectly ordered 3D {ital trans}-(CH){sub {ital x}}. To establish a connection with earlier work, we demonstrate that by artificially decreasing interchain effects and/or increasing the intrachain electron-phonon coupling we can cause polarons and bipolarons to form.« less
  • Over the last decade, Handy and Bessis have developed a moment-problem-based, multiscale quantization theory, the eigenvalue moment method (EMM), which has proven effective in solving singular, strongly coupled, multidimensional Schr{umlt o}dinger Hamiltonians. We extend the scope of EMM by demonstrating its essential role in the generation of wavelet transforms for one-dimensional quantum systems. Combining this with the function-wavelet reconstruction formulas currently available, we are able to recover the wave function systematically, from first principles, through a multiscale process proceeding from large spatial scales to smaller ones. This accomplishment also addresses another outstanding problem, that of reconstructing a function from itsmore » moments. For the class of problems considered, the combined EMM-wavelet analysis yields a definitive solution. {copyright} {ital 1996 The American Physical Society.}« less
  • First-principles local-density-functional calculations have been used to investigate the equilibrium point defect structure and boron-defect interactions in Ni{sub 3}Al. The dominant point defect types in off-stoichiometric Ni{sub 3}Al are substitutional antisite defects on both sublattices. The boron binding energy is dependent on lattice coordination; it is strongest near vacancy sites with a nearest-neighbor nickel coordination number of about four (instead of six as in the defect-free interstitial site) and with no aluminum atom nearest-neighbors. This suggests that boron tends to segregate to open defect sites and to enhance cohesion through the formation of localized Ni-B covalent bonds. Comparison of themore » binding energies of boron and carbon in Ni{sub 3}Al shows that boron has a stronger tendency to segregate to open sites than carbon.« less
  • The electronic properties, structure and phase transformation of UO2 have been studied from first principles by the all-electron projector-augmented-wave (PAW) method. The generalized gradient approximation (GGA)+U formalism has been used to account for the strong on-site Coulomb repulsion among the localized U 5f electrons. GGA+U gives an antiferromagnetic insulating ground state for the effective Hubbard parameter Ueff ≥2.0 eV and this ordering is consistent with experimental measurement. Our results also reveal that by choosing an appropriate Ueff =3.0 eV it is possible to consistently describe structural properties of UO2 and model phase transition processes. The distribution of the local electrostaticmore » potential indicated that the phase transition pressure for UO2 under operant conditions is about 20 GPa. In addition, the formation energies of intrinsic defects, which play a critical role in UO2 fuel under operant conditions, are found to be depended on whether the environment is under U-rich condition or O-rich condition.« less