Atomic diffusion in the surface state of Mott insulator NiS2

C. Clark; S. Friedemann

doi:10.1016/j.jmmm.2015.08.012

Atomic diffusion in the surface state of Mott insulator NiS₂

C. Clark, S. Friedemann^*

^*Corresponding author for this work

School of Physics

Research output: Contribution to journal › Article (Academic Journal) › peer-review

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Abstract

We present resistivity measurements of Mott insulator NiS₂ single crystals after heat treatment. We find a strong increase of the low temperature resistivity that relaxes back towards the pristine behaviour over several days with a time constant of 45 h at room temperature. The low temperature resistivity has previously been shown to be dominated by surface conduction (Thio and Bennett, 1994 [1]). Consequently, the changes induced by heat treatment are attributed to changes of surface states. Our results suggest the creation of vacancies in the surface that are refilled from the bulk via atomic diffusion. We estimate a diffusion constant of D 1×^10-10 ^m2 ^s-1 at room temperature. We identify sulphur vacancies as the most likely to form via oxidisation of sulphur forming volatile SO₂ during heat treatment. Our results point towards these sulphur vacancies to be the source of surface state localisation in NiS₂.

Original language	English
Pages (from-to)	56-61
Number of pages	6
Journal	Journal of Magnetism and Magnetic Materials
Volume	400
DOIs	https://doi.org/10.1016/j.jmmm.2015.08.012
Publication status	Published - 15 Feb 2016
Event	ICM2015: 20th International Conference on Magnetism - Palau de Congressos de Catalunya, Barcelona, Spain Duration: 5 Jul 2015 → 10 Jul 2015

Bibliographical note

Special Issue: Proceedings of the 20th International Conference on Magnetism (Barcelona) 5-10 July 2015. Edited by José Rivas and Domique Givord.

Keywords

Diffusion
Mott insulator
NiS
Surface state

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10.1016/j.jmmm.2015.08.012

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http://arxiv.org/abs/1508.05020Licence: Other

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title = "Atomic diffusion in the surface state of Mott insulator NiS2",

abstract = "We present resistivity measurements of Mott insulator NiS2 single crystals after heat treatment. We find a strong increase of the low temperature resistivity that relaxes back towards the pristine behaviour over several days with a time constant of 45 h at room temperature. The low temperature resistivity has previously been shown to be dominated by surface conduction (Thio and Bennett, 1994 [1]). Consequently, the changes induced by heat treatment are attributed to changes of surface states. Our results suggest the creation of vacancies in the surface that are refilled from the bulk via atomic diffusion. We estimate a diffusion constant of D 1×10-10 m2 s-1 at room temperature. We identify sulphur vacancies as the most likely to form via oxidisation of sulphur forming volatile SO2 during heat treatment. Our results point towards these sulphur vacancies to be the source of surface state localisation in NiS2.",

keywords = "Diffusion, Mott insulator, NiS, Surface state",

author = "C. Clark and S. Friedemann",

note = "Special Issue: Proceedings of the 20th International Conference on Magnetism (Barcelona) 5-10 July 2015. Edited by Jos{\'e} Rivas and Domique Givord.; ICM2015: 20th International Conference on Magnetism ; Conference date: 05-07-2015 Through 10-07-2015",

year = "2016",

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day = "15",

doi = "10.1016/j.jmmm.2015.08.012",

language = "English",

volume = "400",

pages = "56--61",

journal = "Journal of Magnetism and Magnetic Materials",

issn = "0304-8853",

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TY - JOUR

T1 - Atomic diffusion in the surface state of Mott insulator NiS2

AU - Clark, C.

AU - Friedemann, S.

N1 - Special Issue: Proceedings of the 20th International Conference on Magnetism (Barcelona) 5-10 July 2015. Edited by José Rivas and Domique Givord.

PY - 2016/2/15

Y1 - 2016/2/15

N2 - We present resistivity measurements of Mott insulator NiS2 single crystals after heat treatment. We find a strong increase of the low temperature resistivity that relaxes back towards the pristine behaviour over several days with a time constant of 45 h at room temperature. The low temperature resistivity has previously been shown to be dominated by surface conduction (Thio and Bennett, 1994 [1]). Consequently, the changes induced by heat treatment are attributed to changes of surface states. Our results suggest the creation of vacancies in the surface that are refilled from the bulk via atomic diffusion. We estimate a diffusion constant of D 1×10-10 m2 s-1 at room temperature. We identify sulphur vacancies as the most likely to form via oxidisation of sulphur forming volatile SO2 during heat treatment. Our results point towards these sulphur vacancies to be the source of surface state localisation in NiS2.

AB - We present resistivity measurements of Mott insulator NiS2 single crystals after heat treatment. We find a strong increase of the low temperature resistivity that relaxes back towards the pristine behaviour over several days with a time constant of 45 h at room temperature. The low temperature resistivity has previously been shown to be dominated by surface conduction (Thio and Bennett, 1994 [1]). Consequently, the changes induced by heat treatment are attributed to changes of surface states. Our results suggest the creation of vacancies in the surface that are refilled from the bulk via atomic diffusion. We estimate a diffusion constant of D 1×10-10 m2 s-1 at room temperature. We identify sulphur vacancies as the most likely to form via oxidisation of sulphur forming volatile SO2 during heat treatment. Our results point towards these sulphur vacancies to be the source of surface state localisation in NiS2.

KW - Diffusion

KW - Mott insulator

KW - NiS

KW - Surface state

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U2 - 10.1016/j.jmmm.2015.08.012

DO - 10.1016/j.jmmm.2015.08.012

M3 - Article (Academic Journal)

AN - SCOPUS:84949316500

SN - 0304-8853

VL - 400

SP - 56

EP - 61

JO - Journal of Magnetism and Magnetic Materials

JF - Journal of Magnetism and Magnetic Materials

T2 - ICM2015: 20th International Conference on Magnetism

Y2 - 5 July 2015 through 10 July 2015

ER -

Atomic diffusion in the surface state of Mott insulator NiS₂

Abstract

Bibliographical note

Keywords

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NiS2 resistivity data

Cite this

Atomic diffusion in the surface state of Mott insulator NiS2

Abstract

Bibliographical note

Keywords

Access to Document

Handle.net

Other files and links

Fingerprint

Datasets

NiS2 resistivity data

Cite this

Atomic diffusion in the surface state of Mott insulator NiS₂