Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te

Abstract A remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed t...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Aastha Vasdev, Moinak Dutta, Shivam Mishra, Veerpal Kaur, Harleen Kaur, Kanishka Biswas, Goutam Sheet
Formato: article
Lenguaje:EN
Publicado: Nature Portfolio 2021
Materias:
R
Q
Acceso en línea:https://doaj.org/article/948f21ca2be143858c1e96a5891fcb86
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
id oai:doaj.org-article:948f21ca2be143858c1e96a5891fcb86
record_format dspace
spelling oai:doaj.org-article:948f21ca2be143858c1e96a5891fcb862021-12-02T15:09:23ZLocal ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te10.1038/s41598-021-96299-32045-2322https://doaj.org/article/948f21ca2be143858c1e96a5891fcb862021-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-96299-3https://doaj.org/toc/2045-2322Abstract A remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .Aastha VasdevMoinak DuttaShivam MishraVeerpal KaurHarleen KaurKanishka BiswasGoutam SheetNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-8 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Aastha Vasdev
Moinak Dutta
Shivam Mishra
Veerpal Kaur
Harleen Kaur
Kanishka Biswas
Goutam Sheet
Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
description Abstract A remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .
format article
author Aastha Vasdev
Moinak Dutta
Shivam Mishra
Veerpal Kaur
Harleen Kaur
Kanishka Biswas
Goutam Sheet
author_facet Aastha Vasdev
Moinak Dutta
Shivam Mishra
Veerpal Kaur
Harleen Kaur
Kanishka Biswas
Goutam Sheet
author_sort Aastha Vasdev
title Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
title_short Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
title_full Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
title_fullStr Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
title_full_unstemmed Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te
title_sort local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {sn}}_{0.7}{\text {ge}}_{0.3}{\text {te}}$$ sn 0.7 ge 0.3 te
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/948f21ca2be143858c1e96a5891fcb86
work_keys_str_mv AT aasthavasdev localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT moinakdutta localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT shivammishra localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT veerpalkaur localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT harleenkaur localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT kanishkabiswas localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
AT goutamsheet localferroelectricpolarizationswitchingdrivenbynanoscaledistortionsinthermoelectrictextsn07textge03texttesn07ge03te
_version_ 1718387829095006208