Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Short- and intermediate-range structure of liquid GeSe2
 
research article

Short- and intermediate-range structure of liquid GeSe2

Massobrio, C.
•
Pasquarello, Alfredo  orcid-logo
•
Car, R.
2001
Physical Review B

First-principles molecular dynamics simulations are carried out to study the structural properties of liquid GeSe2. We use a generalized gradient approximation for the exchange and correlation energy, which we find to improve significantly upon the local density approximation in describing both the short- and the intermediate-range structure. A very good agreement with experiment is obtained for the total neutron structure factor over the entire range of momentum transfer. In particular, the first sharp diffraction peak (FSDP) is well reproduced. We carry out a detailed comparison between partial structure factors and partial pair correlations in theory and experiment to assess the quality of our simulation model. The short-range and intermediate-range structure are well described overall. However, residual differences between theory and experiment, such as the absence of a FSDP in the concentration-concentration structure factor, appear and are traced back to the Ge-Ge correlations. An analysis of the bonding configurations indicates that liquid GeSe2 is a defective network consisting of predominant Ge-centered tetrahedral units, but Ge- and Se-centered triads and homopolar bonds occur in non-negligible amounts. The number of Ge-Ge homopolar bonds and of ordered fourfold rings compare favorably with experimental estimates. Chemical disorder manifests through an important percentage of Se-rich odd-membered rings. We characterized the intermediate-range order by studying the relation between real-space distances and the FSDP. We found that this feature appears when correlations beyond 5 Angstrom are accounted for. The evaluation of bond lifetimes reflect the higher stability of Ge-Se bonds with respect to homopolar bonds, consistent with the predominance of tetrahedral units.

  • Files
  • Details
  • Metrics
Loading...
Thumbnail Image
Name

PhysRevB.64.144205.pdf

Type

Main Document

Version

Published version

Access type

openaccess

License Condition

N/A

Size

168.57 KB

Format

Adobe PDF

Checksum (MD5)

08880d9f0d9c0105b4016bf9701cb3a1

Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés