Ferromagnetism in doped semiconductors without magnetic ions

R. N. Bhatt; Erik Nielsen

doi:10.1142/s0217979208050358

Ferromagnetism in doped semiconductors without magnetic ions

R. N. Bhatt, Erik Nielsen

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

While ferromagnetism has been obtained above 100 K in doped semiconductors with magnetic ions such as Ga_1-xMn_xAs, bulk doped semiconductors in the absence of magnetic ions have shown no tendency towards ferromagnetism. We re-examine the nonmagnetic doped semiconductor system at low carrier densities in terms of a generalized Hubbard model. Using exact diagonalization of the many-body Hamiltonian for finite clusters, we find that the system exhibits significant ferromagnetic tendencies at nanoscales, in a region of parameter space not accessible to bulk systems, but achievable in quantum dots and heterostructures. Implications for studying these effects in experimentally realizable systems, as well as the possibility of true (macroscopic) ferromagnetism in these systems is discussed.

Original language	English (US)
Pages (from-to)	4595-4606
Number of pages	12
Journal	International Journal of Modern Physics B
Volume	22
Issue number	25-26
DOIs	https://doi.org/10.1142/s0217979208050358
State	Published - Oct 20 2008

All Science Journal Classification (ASJC) codes

Statistical and Nonlinear Physics
Condensed Matter Physics

Keywords

Disordered Hubbard model
Nagaoka ferromagnetism
Quantum dots
Shallow impurities

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10.1142/s0217979208050358

Cite this

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title = "Ferromagnetism in doped semiconductors without magnetic ions",

abstract = "While ferromagnetism has been obtained above 100 K in doped semiconductors with magnetic ions such as Ga1-xMnxAs, bulk doped semiconductors in the absence of magnetic ions have shown no tendency towards ferromagnetism. We re-examine the nonmagnetic doped semiconductor system at low carrier densities in terms of a generalized Hubbard model. Using exact diagonalization of the many-body Hamiltonian for finite clusters, we find that the system exhibits significant ferromagnetic tendencies at nanoscales, in a region of parameter space not accessible to bulk systems, but achievable in quantum dots and heterostructures. Implications for studying these effects in experimentally realizable systems, as well as the possibility of true (macroscopic) ferromagnetism in these systems is discussed.",

keywords = "Disordered Hubbard model, Nagaoka ferromagnetism, Quantum dots, Shallow impurities",

author = "Bhatt, {R. N.} and Erik Nielsen",

note = "Funding Information: This work was produced in the normal course of business by employees of Ibis Biosciences, an Abbott company, which develops and markets broad spectrum diagnostic devices and assays. No grant monies were used to support this work.",

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T1 - Ferromagnetism in doped semiconductors without magnetic ions

AU - Bhatt, R. N.

AU - Nielsen, Erik

N1 - Funding Information: This work was produced in the normal course of business by employees of Ibis Biosciences, an Abbott company, which develops and markets broad spectrum diagnostic devices and assays. No grant monies were used to support this work.

PY - 2008/10/20

Y1 - 2008/10/20

N2 - While ferromagnetism has been obtained above 100 K in doped semiconductors with magnetic ions such as Ga1-xMnxAs, bulk doped semiconductors in the absence of magnetic ions have shown no tendency towards ferromagnetism. We re-examine the nonmagnetic doped semiconductor system at low carrier densities in terms of a generalized Hubbard model. Using exact diagonalization of the many-body Hamiltonian for finite clusters, we find that the system exhibits significant ferromagnetic tendencies at nanoscales, in a region of parameter space not accessible to bulk systems, but achievable in quantum dots and heterostructures. Implications for studying these effects in experimentally realizable systems, as well as the possibility of true (macroscopic) ferromagnetism in these systems is discussed.

AB - While ferromagnetism has been obtained above 100 K in doped semiconductors with magnetic ions such as Ga1-xMnxAs, bulk doped semiconductors in the absence of magnetic ions have shown no tendency towards ferromagnetism. We re-examine the nonmagnetic doped semiconductor system at low carrier densities in terms of a generalized Hubbard model. Using exact diagonalization of the many-body Hamiltonian for finite clusters, we find that the system exhibits significant ferromagnetic tendencies at nanoscales, in a region of parameter space not accessible to bulk systems, but achievable in quantum dots and heterostructures. Implications for studying these effects in experimentally realizable systems, as well as the possibility of true (macroscopic) ferromagnetism in these systems is discussed.

KW - Disordered Hubbard model

KW - Nagaoka ferromagnetism

KW - Quantum dots

KW - Shallow impurities

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Ferromagnetism in doped semiconductors without magnetic ions

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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