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Title: Magnetism in undoped ZnS studied from density functional theory

The magnetic property induced by the native defects in ZnS bulk, thin film, and quantum dots are investigated comprehensively based on density functional theory within the generalized gradient approximation + Hubbard U (GGA + U) approach. We find the origin of magnetism is closely related to the introduction of hole into ZnS systems. The relative localization of S-3p orbitals is another key to resulting in unpaired p-electron, due to Hund's rule. For almost all the ZnS systems under study, the magnetic moment arises from the S-dangling bonds generated by Zn vacancies. The charge-neutral Zn vacancy, Zn vacancy in 1− charge sate, and S vacancy in the 1+ charge sate produce a local magnetic moment of 2.0, 1.0, and 1.0 μ{sub B}, respectively. The Zn vacancy in the neutral and 1− charge sates are the important cause for the ferromagnetism in ZnS bulk, with a Curie temperature (T{sub C}) above room temperature. For ZnS thin film with clean (111) surfaces, the spins on each surface are ferromagnetically coupled but antiferromagnetically coupled between two surfaces, which is attributable to the internal electric field between the two polar (111) surfaces of the thin film. Only surface Zn vacancies can yield local magnetic moment for ZnS thinmore » film and quantum dot, which is ascribed to the surface effect. Interactions between magnetic moments on S-3p states induced by hole-doping are responsible for the ferromagnetism observed experimentally in various ZnS samples.« less
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Department of Physics and Mathematics, Hunan Institute of Engineering, Xiangtan 411104 (China)
  2. School of Physics and Microelectronics and Key Lab for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha 410082 (China)
  3. College of Physics and Electronic Engineering, Caili University, Kaili 556011 (China)
Publication Date:
OSTI Identifier:
22304257
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; CURIE POINT; DENSITY FUNCTIONAL METHOD; ELECTRIC FIELDS; FERROMAGNETISM; INTERACTIONS; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; P STATES; QUANTUM DOTS; SPIN; SURFACES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VACANCIES; ZINC SULFIDES