Phonon anomalies predict superconducting Tc for AlB2-type structures
We show that the well-known Kohn anomaly predicts Tc for ordered AlB2-type structures. We use ab initio Density Functional Theory to calculate phonon dispersions for Mg1-xAlxB2 compositions and identify a phonon anomaly with magnitude that predicts experimental values of Tc for all x. Key features of these anomalies correlate with the electronic structure of Mg1-xAlxB2. This approach predicts Tc for other known AlB2-type structures as well as new compositions. We predict that Mg0.5Ba0.5B2 will show Tc = 63.6 ± 6.6 K. Other forms of the Mg1-xBaxB2 series will also be superconductors when successfully synthesised. Our calculations predict that the end-member composition, BaB2, is likely to show a Tc significantly higher than currently achieved by other diborides although an applied pressure ~16 GPa may be required to stabilise the structure.
Impact and interest:
Citation counts are sourced monthly from and citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from theindexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
|Item Type:||Journal Article|
|Additional Information:||First published online: 28 Aug 2015|
|Keywords:||Density Functional Theory, Magnesium Diboride, Phonon Anomaly, Superconducting transition temperature, Electronic band structure|
|Subjects:||Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CONDENSED MATTER PHYSICS (020400) > Condensed Matter Modelling and Density Functional Theory (020403)
Australian and New Zealand Standard Research Classification > PHYSICAL SCIENCES (020000) > CONDENSED MATTER PHYSICS (020400) > Electronic and Magnetic Properties of Condensed Matter; Superconductivity (020404)
Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > THEORETICAL AND COMPUTATIONAL CHEMISTRY (030700)
|Divisions:||Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2015 Royal Society of Chemistry|
|Copyright Statement:||This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.|
|Deposited On:||10 Sep 2015 23:28|
|Last Modified:||11 Jan 2016 04:49|
Repository Staff Only: item control page