Unbiased Monte Carlo simulations of realistic models: Colossal magnetoresistive manganites

Cengiz Şen; Gonzalo Alvarez; Adriana Moreo; Elbio Dagotto

doi:10.1016/j.phpro.2010.09.043

Unbiased Monte Carlo simulations of realistic models: Colossal magnetoresistive manganites

Cengiz Şen, Gonzalo Alvarez, Adriana Moreo, Elbio Dagotto

Computational Chemistry and Nanomaterial

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

2 Scopus citations

Abstract

We investigate the one-orbital model for manganites with cooperative phonons and superexchange coupling J_AF via large-scale Monte Carlo (MC) simulations. Results for two-orbitals are also briefly discussed. Focusing on an the realistic electronic density n = 0.75, a regime of competition between ferromagnetic (FM) metallic and charge-ordered (CO) insulating states was identified in the finite temperature phase diagram. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects were observed. The CMR magnitude is much larger than recently reported when randomly distributed polarons form the competing insulator. The appearance of CMR is associated with the development of short-distance correlations among polarons, above the spin ordering temperatures, resembling the charge arrangement of the low-temperature CO state. We present calculations of charge-charge correlations as well as typical Monte Carlo snapshots to support this view.

Original language	English
Pages (from-to)	39-51
Number of pages	13
Journal	Physics Procedia
Volume	7
DOIs	https://doi.org/10.1016/j.phpro.2010.09.043
State	Published - 2010

Funding

We acknowledgesupport via the NSF grant DMR-0443144 and the LDRD program at ORNL. This research used resources of the National Center for Computational Sciences. GA is sponsored by the Division of Scientific User Facilities, Basic Energy Sciences, DOE, under contract DE-AC05-00OR22725with Oak Ridge National Laboratory, managed by UT-Battelle.

Funders	Funder number
DE-AC05-00OR22725with
Division of Scientific User Facilities
UT-Battelle
National Science Foundation	DMR-0443144
U.S. Department of Energy
Directorate for Mathematical and Physical Sciences	0443144
Basic Energy Sciences
Oak Ridge National Laboratory
Laboratory Directed Research and Development

Keywords

Colossal magnetoresistance
Double-exchange model
Manganites
Monte Carlo

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10.1016/j.phpro.2010.09.043

Cite this

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title = "Unbiased Monte Carlo simulations of realistic models: Colossal magnetoresistive manganites",

abstract = "We investigate the one-orbital model for manganites with cooperative phonons and superexchange coupling JAF via large-scale Monte Carlo (MC) simulations. Results for two-orbitals are also briefly discussed. Focusing on an the realistic electronic density n = 0.75, a regime of competition between ferromagnetic (FM) metallic and charge-ordered (CO) insulating states was identified in the finite temperature phase diagram. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects were observed. The CMR magnitude is much larger than recently reported when randomly distributed polarons form the competing insulator. The appearance of CMR is associated with the development of short-distance correlations among polarons, above the spin ordering temperatures, resembling the charge arrangement of the low-temperature CO state. We present calculations of charge-charge correlations as well as typical Monte Carlo snapshots to support this view.",

keywords = "Colossal magnetoresistance, Double-exchange model, Manganites, Monte Carlo",

author = "Cengiz {\c S}en and Gonzalo Alvarez and Adriana Moreo and Elbio Dagotto",

year = "2010",

doi = "10.1016/j.phpro.2010.09.043",

language = "English",

volume = "7",

pages = "39--51",

journal = "Physics Procedia",

issn = "1875-3884",

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TY - JOUR

T1 - Unbiased Monte Carlo simulations of realistic models

T2 - Colossal magnetoresistive manganites

AU - Şen, Cengiz

AU - Alvarez, Gonzalo

AU - Moreo, Adriana

AU - Dagotto, Elbio

PY - 2010

Y1 - 2010

N2 - We investigate the one-orbital model for manganites with cooperative phonons and superexchange coupling JAF via large-scale Monte Carlo (MC) simulations. Results for two-orbitals are also briefly discussed. Focusing on an the realistic electronic density n = 0.75, a regime of competition between ferromagnetic (FM) metallic and charge-ordered (CO) insulating states was identified in the finite temperature phase diagram. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects were observed. The CMR magnitude is much larger than recently reported when randomly distributed polarons form the competing insulator. The appearance of CMR is associated with the development of short-distance correlations among polarons, above the spin ordering temperatures, resembling the charge arrangement of the low-temperature CO state. We present calculations of charge-charge correlations as well as typical Monte Carlo snapshots to support this view.

AB - We investigate the one-orbital model for manganites with cooperative phonons and superexchange coupling JAF via large-scale Monte Carlo (MC) simulations. Results for two-orbitals are also briefly discussed. Focusing on an the realistic electronic density n = 0.75, a regime of competition between ferromagnetic (FM) metallic and charge-ordered (CO) insulating states was identified in the finite temperature phase diagram. In the vicinity of the associated bicritical point, colossal magnetoresistance (CMR) effects were observed. The CMR magnitude is much larger than recently reported when randomly distributed polarons form the competing insulator. The appearance of CMR is associated with the development of short-distance correlations among polarons, above the spin ordering temperatures, resembling the charge arrangement of the low-temperature CO state. We present calculations of charge-charge correlations as well as typical Monte Carlo snapshots to support this view.

KW - Colossal magnetoresistance

KW - Double-exchange model

KW - Manganites

KW - Monte Carlo

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DO - 10.1016/j.phpro.2010.09.043

M3 - Article

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SN - 1875-3884

VL - 7

SP - 39

EP - 51

JO - Physics Procedia

JF - Physics Procedia

ER -

Unbiased Monte Carlo simulations of realistic models: Colossal magnetoresistive manganites

Abstract

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Keywords

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