Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials
Unusual force constants originating from the local charge distribution in crystalline GeTe and Sb<sub>2</sub>Te<sub>3</sub> are observed by using the first-principles calculations. The calculated stretching force constants of the second nearest-neighbor Sb-Te and Ge-Te bonds...
Main Authors: | , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2021-06-01
|
Series: | Materials |
Subjects: | |
Online Access: | https://www.mdpi.com/1996-1944/14/13/3514 |
id |
doaj-661288880560452f8cb9ff4ca82a537d |
---|---|
record_format |
Article |
spelling |
doaj-661288880560452f8cb9ff4ca82a537d2021-07-15T15:40:21ZengMDPI AGMaterials1996-19442021-06-01143514351410.3390/ma14133514Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change MaterialsJiong Wang0Dongyu Cui1Yi Kong2Luming Shen3Powder Metallurgy Research Institute, Central South University, Changsha 410083, ChinaPowder Metallurgy Research Institute, Central South University, Changsha 410083, ChinaPowder Metallurgy Research Institute, Central South University, Changsha 410083, ChinaSchool of Civil Engineering, The University of Sydney, Sydney, NSW 2006, AustraliaUnusual force constants originating from the local charge distribution in crystalline GeTe and Sb<sub>2</sub>Te<sub>3</sub> are observed by using the first-principles calculations. The calculated stretching force constants of the second nearest-neighbor Sb-Te and Ge-Te bonds are 0.372 and −0.085 eV/Å<sup>2</sup>, respectively, which are much lower than 1.933 eV/Å<sup>2</sup> of the first nearest-neighbor bonds although their lengths are only 0.17 Å and 0.33 Å longer as compared to the corresponding first nearest-neighbor bonds. Moreover, the bending force constants of the first and second nearest-neighbor Ge-Ge and Sb-Sb bonds exhibit large negative values. Our first-principles molecular dynamic simulations also reveal the possible amorphization of Sb<sub>2</sub>Te<sub>3</sub> through local distortions of the bonds with weak and strong force constants, while the crystalline structure remains by the X-ray diffraction simulation. By identifying the low or negative force constants, these weak atomic interactions are found to be responsible for triggering the collapse of the long-range order. This finding can be utilized to guide the design of functional components and devices based on phase change materials with lower energy consumption.https://www.mdpi.com/1996-1944/14/13/3514unusual force constantphase change materialsGeTeSb<sub>2</sub>Te<sub>3</sub> |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Jiong Wang Dongyu Cui Yi Kong Luming Shen |
spellingShingle |
Jiong Wang Dongyu Cui Yi Kong Luming Shen Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials Materials unusual force constant phase change materials GeTe Sb<sub>2</sub>Te<sub>3</sub> |
author_facet |
Jiong Wang Dongyu Cui Yi Kong Luming Shen |
author_sort |
Jiong Wang |
title |
Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials |
title_short |
Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials |
title_full |
Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials |
title_fullStr |
Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials |
title_full_unstemmed |
Unusual Force Constants Guided Distortion-Triggered Loss of Long-Range Order in Phase Change Materials |
title_sort |
unusual force constants guided distortion-triggered loss of long-range order in phase change materials |
publisher |
MDPI AG |
series |
Materials |
issn |
1996-1944 |
publishDate |
2021-06-01 |
description |
Unusual force constants originating from the local charge distribution in crystalline GeTe and Sb<sub>2</sub>Te<sub>3</sub> are observed by using the first-principles calculations. The calculated stretching force constants of the second nearest-neighbor Sb-Te and Ge-Te bonds are 0.372 and −0.085 eV/Å<sup>2</sup>, respectively, which are much lower than 1.933 eV/Å<sup>2</sup> of the first nearest-neighbor bonds although their lengths are only 0.17 Å and 0.33 Å longer as compared to the corresponding first nearest-neighbor bonds. Moreover, the bending force constants of the first and second nearest-neighbor Ge-Ge and Sb-Sb bonds exhibit large negative values. Our first-principles molecular dynamic simulations also reveal the possible amorphization of Sb<sub>2</sub>Te<sub>3</sub> through local distortions of the bonds with weak and strong force constants, while the crystalline structure remains by the X-ray diffraction simulation. By identifying the low or negative force constants, these weak atomic interactions are found to be responsible for triggering the collapse of the long-range order. This finding can be utilized to guide the design of functional components and devices based on phase change materials with lower energy consumption. |
topic |
unusual force constant phase change materials GeTe Sb<sub>2</sub>Te<sub>3</sub> |
url |
https://www.mdpi.com/1996-1944/14/13/3514 |
work_keys_str_mv |
AT jiongwang unusualforceconstantsguideddistortiontriggeredlossoflongrangeorderinphasechangematerials AT dongyucui unusualforceconstantsguideddistortiontriggeredlossoflongrangeorderinphasechangematerials AT yikong unusualforceconstantsguideddistortiontriggeredlossoflongrangeorderinphasechangematerials AT lumingshen unusualforceconstantsguideddistortiontriggeredlossoflongrangeorderinphasechangematerials |
_version_ |
1721298985848668160 |