Photoexcitation-Induced Nonthermal Ultrafast Loss of Long-Range Order in GeTe

被引：1

作者：

Yang, Liqiu ^{[1
]}

Tiwari, Subodh C. ^{[1
]}

Fukushima, Shogo ^{[2
]}

Shimojo, Fuyuki ^{[2
]}

Kalia, Rajiv K. ^{[1
]}

Nakano, Aiichiro ^{[1
]}

Vashishta, Priya ^{[1
]}

Branicio, Paulo S. ^{[3
]}

机构：

[1] Univ Southern Calif, Collaboratory Adv Comp & Simulat, Los Angeles, CA 90089 USA

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

[3] Univ Southern Calif, Mork Family Dept Chem Engn & Mat Sci, Los Angeles, CA 90089 USA

来源：

JOURNAL OF PHYSICAL CHEMISTRY LETTERS | 2022年 / 13卷 / 43期

基金：

美国国家科学基金会;

关键词：

PHASE-CHANGE MATERIALS; MOLECULAR-DYNAMICS; DENSITY; SOLIDS;

D O I：

10.1021/acs.jpclett.2c02448

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Nonadiabatic quantum molecular dynamics is used to investigate the evolution of GeTe photoexcited states. Results reveal a photoexcitation-induced picosecond nonthermal path for the loss of long-range order. A valence electron excitation threshold of 4% is found to trigger local disorder by switching Ge atoms from octahedral to tetrahedral sites and promoting Ge-Ge bonding. The resulting loss of long-range order for a higher valence electron excitation fraction is achieved without fulfilling the Lindemann criterion for melting, therefore utilizing a nonthermal path. The photoexcitation-induced structural disorder is accompanied by charge transfer from Te to Ge, Ge-Te bonding-to-antibonding, and Ge-Ge antibonding-to-bonding change, triggering Ge-Te bond breaking and promoting the formation of Ge-Ge wrong bonds. These results provide an electronic-structure basis to understand the photoexcitation-induced ultrafast changes in the structure and properties of GeTe and other phase-change materials.

引用

页码：10230 / 10236

页数：7

共 50 条

[1] Structural phase transitions on the nanoscale:: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe
Akola, J.
Jones, R. O.
[J]. PHYSICAL REVIEW B, 2007, 76 (23):
[2] PROJECTOR AUGMENTED-WAVE METHOD
BLOCHL, PE
[J]. PHYSICAL REVIEW B, 1994, 50 (24): : 17953 - 17979
[3] Atomistic insights into the nanosecond long amorphization and crystallization cycle of nanoscale Ge2Sb2Te5: An ab initio molecular dynamics study
Branicio, Paulo S.
Bai, Kewu
Ramanarayan, H.
Wu, David T.
Sullivan, Michael B.
Srolovitz, David J.
[J]. PHYSICAL REVIEW MATERIALS, 2018, 2 (04):
[4] Nanosecond switching in GeTe phase change memory cells
Bruns, G.
Merkelbach, P.
Schlockermann, C.
Salinga, M.
Wuttig, M.
Happ, T. D.
Philipp, J. B.
Kund, M.
[J]. APPLIED PHYSICS LETTERS, 2009, 95 (04)
[5] UNIFIED APPROACH FOR MOLECULAR-DYNAMICS AND DENSITY-FUNCTIONAL THEORY
CAR, R
PARRINELLO, M
[J]. PHYSICAL REVIEW LETTERS, 1985, 55 (22) : 2471 - 2474
[6] Coexistence of tetrahedral- and octahedral-like sites in amorphous phase change materials
Caravati, S.
Bernasconi, M.
K hne, T. D.
Krack, M.
Parrinello, M.
[J]. APPLIED PHYSICS LETTERS, 2007, 91 (17)
[7] Casida M.E., 2011, RECENT ADV DENSITY F, P155, DOI [10.1142/9789812830586_0005, DOI 10.1142/9789812830586_0005]
[8] Cornwell J.F., 1969, GROUP THEORY ELECT E
[9] Insights into the structure of the stable and metastable (GeTe)m(Sb2Te3)n compounds
Da Silva, Juarez L. F.
Walsh, Aron
Lee, Hosun
[J]. PHYSICAL REVIEW B, 2008, 78 (22):
[10] Microscopic Complexity in Phase-Change Materials and its Role for Applications
Deringer, Volker L.
Dronskowski, Richard
Wuttig, Matthias
[J]. ADVANCED FUNCTIONAL MATERIALS, 2015, 25 (40) : 6343 - 6359

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