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Title: Comparison Between Experiment and Calculated Band Structures for DyN and SmN

Abstract

We investigate the electronic band structure of two of the rare-earth nitrides, DyN and SmN. Resistivity measurements imply that both materials have a semiconducting ground state, and both show resistivity anomalies coinciding with the magnetic transition, despite the different magnetic states in DyN and SmN. X-ray absorption and emission measurements are in excellent agreement with densities of states obtained from LSDA+U calculations, although for SmN the calculations predict a zero band gap.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
960013
Report Number(s):
BNL-82999-2009-JA
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US1005870
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B: Condensed Matter and Materials Physics; Journal Volume: 76; Journal Issue: 24
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; GROUND STATES; NITRIDES; DYSPROSIUM NITRIDES; SAMARIUM NITRIDES; MATERIALS; national synchrotron light source

Citation Formats

Preston,A., Granville, S., Housden, D., Ludbrook, B., Ruck, B., Trodahl, H., Bittar, A., Williams, G., Downes, J., and et al. Comparison Between Experiment and Calculated Band Structures for DyN and SmN. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.76.245120.
Preston,A., Granville, S., Housden, D., Ludbrook, B., Ruck, B., Trodahl, H., Bittar, A., Williams, G., Downes, J., & et al. Comparison Between Experiment and Calculated Band Structures for DyN and SmN. United States. doi:10.1103/PhysRevB.76.245120.
Preston,A., Granville, S., Housden, D., Ludbrook, B., Ruck, B., Trodahl, H., Bittar, A., Williams, G., Downes, J., and et al. Mon . "Comparison Between Experiment and Calculated Band Structures for DyN and SmN". United States. doi:10.1103/PhysRevB.76.245120.
@article{osti_960013,
title = {Comparison Between Experiment and Calculated Band Structures for DyN and SmN},
author = {Preston,A. and Granville, S. and Housden, D. and Ludbrook, B. and Ruck, B. and Trodahl, H. and Bittar, A. and Williams, G. and Downes, J. and et al},
abstractNote = {We investigate the electronic band structure of two of the rare-earth nitrides, DyN and SmN. Resistivity measurements imply that both materials have a semiconducting ground state, and both show resistivity anomalies coinciding with the magnetic transition, despite the different magnetic states in DyN and SmN. X-ray absorption and emission measurements are in excellent agreement with densities of states obtained from LSDA+U calculations, although for SmN the calculations predict a zero band gap.},
doi = {10.1103/PhysRevB.76.245120},
journal = {Physical Review B: Condensed Matter and Materials Physics},
number = 24,
volume = 76,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • A single-band approach for semiconductor clusters which accounts for the nonparabolicity of the energy bands was recently used by Rama Krishna and Friesner [M.V. Rama Krishna and R.A. Friesner, Phys. Rev. Lett. {bold 67}, 629 (1991)]. We compare the results of this method (denoted here as single-band truncated-crystal, or SBTC, approximation) with a direct pseudopotential band-structure calculation for free-standing hydrogen-passivated GaAs quantum films, wires, and dots. The direct pseudopotential calculation, which includes coupling between all bands, shows that isolated GaAs quantum films, wires, and dots have an indirect band gap for thicknesses below 16, 28, and at least 30 Amore » (8, 14, and at least 15 ML), respectively; beyond these critical dimensions the transition becomes direct. A comparison of the SBTC approximation with the direct pseudopotential calculation shows that (i) the confinement energy of the valence-band maximum is overestimated by the SBTC method, because the zero-confinement character of this state is neglected; (ii) the confinement energy of the {Gamma}-derived conduction state (direct band gap) is slightly overestimated by the SBTC approximation, mainly because of the assumption of infinite potential barriers at the boundaries; (iii) the confinement energy of the {ital X}-derived conduction state (indirect band gap) is severely underestimated by the SBTC method; (iv) while the SBTC approximation predicts {open_quote}{open_quote}quantum deconfinement{close_quote}{close_quote} (i.e., {ital reduction} of gap as size is reduced) for the direct gap of thin GaAs quantum wires, such effect is not present in the direct pseudopotential calculation. {copyright} {ital 1996 American Institute of Physics.}« less
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