Structural and vibrational anomalies in NiS1.4Se0.6 probed by temperature-dependent Raman spectroscopy

H. S. Alagöz; F. Mustafa; J. Jung; K. H. Chow; N. M. Hamdan; S. El-Khatib; M. Egilmez

doi:10.1016/j.materresbull.2026.114308

Structural and vibrational anomalies in NiS_1.4Se_0.6 probed by temperature-dependent Raman spectroscopy

H. S. Alagöz^*
, F. Mustafa
, J. Jung
, K. H. Chow
, N. M. Hamdan
, S. El-Khatib
, M. Egilmez

^*Corresponding author for this work

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

Abstract

We present a temperature-dependent phonon behavior in NiS_1.4Se_0.6, a strongly correlated transition metal chalcogenide known for exhibiting a metal–insulator transition (MIT). Measurements were conducted in the temperature range of 300 K to 100 K to investigate the evolution of the Raman-active A_g phonon modes associated with Se–Se, S–Se, and S–S vibrations. Our analysis reveals a distinct change in the integrated intensity of these A_g peaks, which coincides with the MIT temperature T_MI of the NiS_1.4Se_0.6 at 150 K. Notably, at 250 K, an additional peak appears in the integrated intensity of the phonon modes coincide with the deviation from Curie–Weiss (C–W) behavior, and the activation energy of small polarons shifts. We discuss the mechanism behind these thermally activated changes.

Original language	English
Article number	114308
Journal	Materials Research Bulletin
Volume	204
DOIs	https://doi.org/10.1016/j.materresbull.2026.114308
State	Published - Nov 2026
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2026

Keywords

Magnetization
Metal–insulator transition
Raman
Small polarons
Transition metal chalcogenide

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1016/j.materresbull.2026.114308

Cite this

@article{00d5d685e8e548df9b15b5065ed64443,

title = "Structural and vibrational anomalies in NiS1.4Se0.6 probed by temperature-dependent Raman spectroscopy",

abstract = "We present a temperature-dependent phonon behavior in NiS1.4Se0.6, a strongly correlated transition metal chalcogenide known for exhibiting a metal{\textendash}insulator transition (MIT). Measurements were conducted in the temperature range of 300 K to 100 K to investigate the evolution of the Raman-active Ag phonon modes associated with Se{\textendash}Se, S{\textendash}Se, and S{\textendash}S vibrations. Our analysis reveals a distinct change in the integrated intensity of these Ag peaks, which coincides with the MIT temperature TMI of the NiS1.4Se0.6 at 150 K. Notably, at 250 K, an additional peak appears in the integrated intensity of the phonon modes coincide with the deviation from Curie{\textendash}Weiss (C{\textendash}W) behavior, and the activation energy of small polarons shifts. We discuss the mechanism behind these thermally activated changes.",

keywords = "Magnetization, Metal{\textendash}insulator transition, Raman, Small polarons, Transition metal chalcogenide",

author = "Alag{\"o}z, \{H. S.\} and F. Mustafa and J. Jung and Chow, \{K. H.\} and Hamdan, \{N. M.\} and S. El-Khatib and M. Egilmez",

note = "Publisher Copyright: {\textcopyright} 2026",

year = "2026",

month = nov,

doi = "10.1016/j.materresbull.2026.114308",

language = "English",

volume = "204",

journal = "Materials Research Bulletin",

issn = "0025-5408",

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TY - JOUR

T1 - Structural and vibrational anomalies in NiS1.4Se0.6 probed by temperature-dependent Raman spectroscopy

AU - Alagöz, H. S.

AU - Mustafa, F.

AU - Jung, J.

AU - Chow, K. H.

AU - Hamdan, N. M.

AU - El-Khatib, S.

AU - Egilmez, M.

PY - 2026/11

Y1 - 2026/11

N2 - We present a temperature-dependent phonon behavior in NiS1.4Se0.6, a strongly correlated transition metal chalcogenide known for exhibiting a metal–insulator transition (MIT). Measurements were conducted in the temperature range of 300 K to 100 K to investigate the evolution of the Raman-active Ag phonon modes associated with Se–Se, S–Se, and S–S vibrations. Our analysis reveals a distinct change in the integrated intensity of these Ag peaks, which coincides with the MIT temperature TMI of the NiS1.4Se0.6 at 150 K. Notably, at 250 K, an additional peak appears in the integrated intensity of the phonon modes coincide with the deviation from Curie–Weiss (C–W) behavior, and the activation energy of small polarons shifts. We discuss the mechanism behind these thermally activated changes.

AB - We present a temperature-dependent phonon behavior in NiS1.4Se0.6, a strongly correlated transition metal chalcogenide known for exhibiting a metal–insulator transition (MIT). Measurements were conducted in the temperature range of 300 K to 100 K to investigate the evolution of the Raman-active Ag phonon modes associated with Se–Se, S–Se, and S–S vibrations. Our analysis reveals a distinct change in the integrated intensity of these Ag peaks, which coincides with the MIT temperature TMI of the NiS1.4Se0.6 at 150 K. Notably, at 250 K, an additional peak appears in the integrated intensity of the phonon modes coincide with the deviation from Curie–Weiss (C–W) behavior, and the activation energy of small polarons shifts. We discuss the mechanism behind these thermally activated changes.

KW - Magnetization

KW - Metal–insulator transition

KW - Raman

KW - Small polarons

KW - Transition metal chalcogenide

UR - https://www.scopus.com/pages/publications/105043189649

U2 - 10.1016/j.materresbull.2026.114308

DO - 10.1016/j.materresbull.2026.114308

M3 - Article

AN - SCOPUS:105043189649

SN - 0025-5408

VL - 204

JO - Materials Research Bulletin

JF - Materials Research Bulletin

M1 - 114308

ER -