Phase-change properties related to anharmonicity of local structure

Min Ahn; Kwang sik Jeong; Sungjin Park; Hoon Jung; Jeonghwa Han; Wonjun Yang; Dasol Kim; Jaehun Park; Mann Ho Cho

doi:10.1016/j.cap.2020.03.019

Phase-change properties related to anharmonicity of local structure

Min Ahn, Kwang sik Jeong, Sungjin Park, Hoon Jung, Jeonghwa Han, Wonjun Yang, Dasol Kim, Jaehun Park, Mann Ho Cho

Department of Physics

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

Abstract

Ge-Sb-Te pseudo-binary compounds are known to be phase-change materials (PCM). Most of these chalcogenide compounds are candidate for future phase-change random access memory (PCRAM) applications since they show abrupt change on crystalline-amorphous phase-change process. For the use in next-generation applications, increase of retention properties and decrease of power needed for phase-change process are required. These phase-change properties depend on various material characteristics, and thermal conductivity is one of them. In this study, to introduce an easier method for evaluating the local structural anharmonicity of phase-change materials, optical pump terahertz (THz) probe experiments were performed. By investigating the phonon behaviours in PCM by this method and comparing them with local structural information extracted from extended X-ray absorption fine structure (EXAFS) on Ge₁Sb₂Te₄ and Ge₂Sb₂Te₅ films, the effects of resonant bonding on lattice anharmonicity and thermal conductivity were determined. As resonant bonding in the local structure get enhanced, local distortion of the system decrease which cause the decrease in anharmonicity. The quantitatively-measured anharmonicity obtained from the optical pump THz probe experiments can be closely related to the structural and electrical properties, thus reflecting well the difference of phase-change properties between Ge₁Sb₂Te₄ and Ge₂Sb₂Te₅ films.

Original language	English
Pages (from-to)	807-816
Number of pages	10
Journal	Current Applied Physics
Volume	20
Issue number	6
DOIs	https://doi.org/10.1016/j.cap.2020.03.019
Publication status	Published - 2020 Jun

Bibliographical note

Funding Information:
We gratefully acknowledge the financial support provided by the Ministry of Trade, Industry & Energy (MOTIE) in Korea (Project No. 10045360 ) and the Korea Semiconductor Research Consortium (KSRC) through a project for developing source technology for future semiconductor devices, and Nano·Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (MSIP) (Grant No. 2016M3A7B4910398 ). In addition, we acknowledge the 10C, 8C, and fs-THz beamline in Pohang accelerator laboratory for their experimental help. Finally, we would like to thank Editage ( www.editage.co.kr ) for English language editing.

Publisher Copyright:
© 2020 Korean Physical Society

All Science Journal Classification (ASJC) codes

Materials Science(all)
Physics and Astronomy(all)

Access to Document

10.1016/j.cap.2020.03.019

Cite this

@article{885c228345244b3f99e25af8aef121c8,

title = "Phase-change properties related to anharmonicity of local structure",

abstract = "Ge-Sb-Te pseudo-binary compounds are known to be phase-change materials (PCM). Most of these chalcogenide compounds are candidate for future phase-change random access memory (PCRAM) applications since they show abrupt change on crystalline-amorphous phase-change process. For the use in next-generation applications, increase of retention properties and decrease of power needed for phase-change process are required. These phase-change properties depend on various material characteristics, and thermal conductivity is one of them. In this study, to introduce an easier method for evaluating the local structural anharmonicity of phase-change materials, optical pump terahertz (THz) probe experiments were performed. By investigating the phonon behaviours in PCM by this method and comparing them with local structural information extracted from extended X-ray absorption fine structure (EXAFS) on Ge1Sb2Te4 and Ge2Sb2Te5 films, the effects of resonant bonding on lattice anharmonicity and thermal conductivity were determined. As resonant bonding in the local structure get enhanced, local distortion of the system decrease which cause the decrease in anharmonicity. The quantitatively-measured anharmonicity obtained from the optical pump THz probe experiments can be closely related to the structural and electrical properties, thus reflecting well the difference of phase-change properties between Ge1Sb2Te4 and Ge2Sb2Te5 films.",

author = "Min Ahn and Jeong, {Kwang sik} and Sungjin Park and Hoon Jung and Jeonghwa Han and Wonjun Yang and Dasol Kim and Jaehun Park and Cho, {Mann Ho}",

note = "Funding Information: We gratefully acknowledge the financial support provided by the Ministry of Trade, Industry & Energy (MOTIE) in Korea (Project No. 10045360 ) and the Korea Semiconductor Research Consortium (KSRC) through a project for developing source technology for future semiconductor devices, and Nano·Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (MSIP) (Grant No. 2016M3A7B4910398 ). In addition, we acknowledge the 10C, 8C, and fs-THz beamline in Pohang accelerator laboratory for their experimental help. Finally, we would like to thank Editage ( www.editage.co.kr ) for English language editing. Publisher Copyright: {\textcopyright} 2020 Korean Physical Society",

year = "2020",

month = jun,

doi = "10.1016/j.cap.2020.03.019",

language = "English",

volume = "20",

pages = "807--816",

journal = "Current Applied Physics",

issn = "1567-1739",

publisher = "Elsevier",

number = "6",

}

TY - JOUR

T1 - Phase-change properties related to anharmonicity of local structure

AU - Ahn, Min

AU - Jeong, Kwang sik

AU - Park, Sungjin

AU - Jung, Hoon

AU - Han, Jeonghwa

AU - Yang, Wonjun

AU - Kim, Dasol

AU - Park, Jaehun

AU - Cho, Mann Ho

N1 - Funding Information: We gratefully acknowledge the financial support provided by the Ministry of Trade, Industry & Energy (MOTIE) in Korea (Project No. 10045360 ) and the Korea Semiconductor Research Consortium (KSRC) through a project for developing source technology for future semiconductor devices, and Nano·Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and Future Planning (MSIP) (Grant No. 2016M3A7B4910398 ). In addition, we acknowledge the 10C, 8C, and fs-THz beamline in Pohang accelerator laboratory for their experimental help. Finally, we would like to thank Editage ( www.editage.co.kr ) for English language editing. Publisher Copyright: © 2020 Korean Physical Society

PY - 2020/6

Y1 - 2020/6

N2 - Ge-Sb-Te pseudo-binary compounds are known to be phase-change materials (PCM). Most of these chalcogenide compounds are candidate for future phase-change random access memory (PCRAM) applications since they show abrupt change on crystalline-amorphous phase-change process. For the use in next-generation applications, increase of retention properties and decrease of power needed for phase-change process are required. These phase-change properties depend on various material characteristics, and thermal conductivity is one of them. In this study, to introduce an easier method for evaluating the local structural anharmonicity of phase-change materials, optical pump terahertz (THz) probe experiments were performed. By investigating the phonon behaviours in PCM by this method and comparing them with local structural information extracted from extended X-ray absorption fine structure (EXAFS) on Ge1Sb2Te4 and Ge2Sb2Te5 films, the effects of resonant bonding on lattice anharmonicity and thermal conductivity were determined. As resonant bonding in the local structure get enhanced, local distortion of the system decrease which cause the decrease in anharmonicity. The quantitatively-measured anharmonicity obtained from the optical pump THz probe experiments can be closely related to the structural and electrical properties, thus reflecting well the difference of phase-change properties between Ge1Sb2Te4 and Ge2Sb2Te5 films.

AB - Ge-Sb-Te pseudo-binary compounds are known to be phase-change materials (PCM). Most of these chalcogenide compounds are candidate for future phase-change random access memory (PCRAM) applications since they show abrupt change on crystalline-amorphous phase-change process. For the use in next-generation applications, increase of retention properties and decrease of power needed for phase-change process are required. These phase-change properties depend on various material characteristics, and thermal conductivity is one of them. In this study, to introduce an easier method for evaluating the local structural anharmonicity of phase-change materials, optical pump terahertz (THz) probe experiments were performed. By investigating the phonon behaviours in PCM by this method and comparing them with local structural information extracted from extended X-ray absorption fine structure (EXAFS) on Ge1Sb2Te4 and Ge2Sb2Te5 films, the effects of resonant bonding on lattice anharmonicity and thermal conductivity were determined. As resonant bonding in the local structure get enhanced, local distortion of the system decrease which cause the decrease in anharmonicity. The quantitatively-measured anharmonicity obtained from the optical pump THz probe experiments can be closely related to the structural and electrical properties, thus reflecting well the difference of phase-change properties between Ge1Sb2Te4 and Ge2Sb2Te5 films.

UR - http://www.scopus.com/inward/record.url?scp=85082847379&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85082847379&partnerID=8YFLogxK

U2 - 10.1016/j.cap.2020.03.019

DO - 10.1016/j.cap.2020.03.019

M3 - Article

AN - SCOPUS:85082847379

SN - 1567-1739

VL - 20

SP - 807

EP - 816

JO - Current Applied Physics

JF - Current Applied Physics

IS - 6

ER -

Phase-change properties related to anharmonicity of local structure

Abstract

Bibliographical note

All Science Journal Classification (ASJC) codes

Access to Document

Other files and links

Fingerprint

Cite this