Longitudinal acoustic and higher-energy excitations in the liquid phase-change material Ge2Sb2Te5

被引：3

作者：

Inui, M. ^{[1
]}

Kajihara, Y. ^{[1
]}

Hosokawa, S. ^{[2
,8
]}

Chiba, A. ^{[3
]}

Nakajima, Y. ^{[2
]}

Matsuda, K. ^{[2
]}

Tsuchiya, Y. ^{[4
]}

Stellhorn, J. R. ^{[1
]}

Hagiya, T. ^{[5
,9
]}

Uchiyama, H. ^{[6
]}

Tsutsui, S. ^{[6
]}

Baron, A. Q. R. ^{[7
]}

机构：

[1] Hiroshima Univ, Grad Sch Adv Sci & Engn, Higashihiroshima 7398521, Japan

[2] Kumamoto Univ, Dept Phys, Kumamoto 8608555, Japan

[3] Keio Univ, Dept Phys, Yokohama, Kanagawa 2238522, Japan

[4] Niigata Univ, Niigata 9502181, Japan

[5] Kyoto Univ, Grad Sch Sci, Kyoto 6068502, Japan

[6] Japan Synchrotron Radiat Res Inst JASRI, Sayo, Hyogo 6795198, Japan

[7] RIKEN SPring 8 Ctr, Mat Dynam Lab, Sayo, Hyogo 6795148, Japan

[8] Kumamoto Univ, Inst Ind Nanomat, Kumamoto 8608555, Japan

[9] Sanyo Special Steel Co Ltd, Met Powder Technol Dept, Himeji, Hyogo 6728677, Japan

来源：

PHYSICAL REVIEW B | 2021年 / 104卷 / 06期

基金：

日本学术振兴会;

关键词：

PEIERLS DISTORTION; CRYSTALLIZATION; DYNAMICS;

D O I：

10.1103/PhysRevB.104.064202

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The dynamic structure factor S(Q, E) of liquid Ge2Sb2Te5 has been obtained by inelastic x-ray scattering, where Q and E are momentum and energy transfer, respectively. The dispersion curve of the longitudinal acoustic excitation energy exhibits flat-topped Q dependence similarly to that in liquid GeTe and liquid Bi, where the local structure is modulated by Peierls distortion. The flat-topped energy in liquid Ge2Sb2Te5 is split into low and high energy parts arising from Sb-Te and Ge-Te correlations, respectively. Furthermore, the high energy part depends on Q like an optical mode with decreasing Q to zero, and it approaches the vibrational energy of fourfold coordinated Ge atoms with octahedral configurations. The result indicates that a majority of Ge in the liquid stays in octahedral order as predicted by first-principles molecular dynamics simulations.

引用

页数：8

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