uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Electronic and mechanical properties of Cr2GeC with hybrid functional and correlation effects
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
2012 (English)In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 152, no 13, 1147-1149 p.Article in journal (Refereed) Published
Abstract [en]

We present a computational study of the MAX phase material Cr2GeC to obtain its crystal and electronic structure using density functional theory with various exchange-correlation functionals. While the GGA and GGA+U methods are giving a reasonable description of the lattice parameters, the hybrid functional (HSE06) is found to give too large values. Then, on the basis of our GGA+U calculations, the antiferromagnetic ordering is found to be the ground state. Furthermore, we study the charge distribution between the constituent elements of this compound and find that the simple ionic model fails to describe it due to the complex nature of this material. Finally, we conclude that the treatment of the correlated electrons is important for the correct description of this material. 

Place, publisher, year, edition, pages
2012. Vol. 152, no 13, 1147-1149 p.
Keyword [en]
MAX phases, Hybrid functional, Electronic structure, Mechanical properties
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-177581DOI: 10.1016/j.ssc.2012.03.044ISI: 000305313800015OAI: oai:DiVA.org:uu-177581DiVA: diva2:541238
Available from: 2012-07-16 Created: 2012-07-16 Last updated: 2014-01-08
In thesis
1. Structural, Electronic and Mechanical Properties of Advanced Functional Materials
Open this publication in new window or tab >>Structural, Electronic and Mechanical Properties of Advanced Functional Materials
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The search for alternate and renewable energy resources as well as the efficient use of energy and development of such systems that can help to save the energy consumption is needed because of exponential growth in world population, limited conventional fossil fuel resources, and to meet the increasing demand of clean and environment friendly substitutes. Hydrogen being the simplest, most abundant and clean energy carrier has the potential to fulfill some of these requirements provided the development of efficient, safe and durable systems for its production, storage and usage.

Chemical hydrides, complex hydrides and nanomaterials, where the hydrogen is either chemically bonded to the metal ions or physiosorbed, are the possible means to overcome the difficulties associated with the storage and usage of hydrogen at favorable conditions. We have studied the structural and electronic properties of some of the chemical hydrides, complex hydrides and functionalized nanostructures to understand the kinetics and thermodynamics of these materials.

Another active field relating to energy storage is rechargeable batteries. We have studied the detailed crystal and electronic structures of Li and Mg based cathode materials and calculated the average intercalation voltage of the corresponding batteries. We found that transition metal doped MgH2 nanocluster is a material to use efficiently not only in batteries but also in fuel-cell technologies.

MAX phases can be used to develop the systems to save the energy consumption. We have chosen one compound from each of all known types of MAX phases and analyzed the structural, electronic, and mechanical properties using the hybrid functional. We suggest that the proper treatment of correlation effects is important for the correct description of Cr2AlC and Cr2GeC by the good choice of Hubbard 'U' in DFT+U method.

Hydrogen is fascinating to physicists due to predicted possibility of metallization and high temperature superconductivity. On the basis of our ab initio molecular dynamics studies, we propose that the recent claim of conductive hydrogen by experiments might be explained by the diffusion of hydrogen at relevant pressure and temperature.

In this thesis we also present the studies of phase change memory materials, oxides and amorphization of oxide materials, spintronics and sulfide materials.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 98 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1062
DFT, Hydrogen storage, Rechargeable batteries, Amorphization, Electronic structure, Crystal strcuture, Molecular dynamics, Diffusion, Intercalation voltage, High pressure, MAX phases, Mechanical properties, Optical properties, Phase change memory, Spintronics, Magnetism, Correlation effects, Band structure
National Category
Physical Sciences
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
urn:nbn:se:uu:diva-205243 (URN)978-91-554-8723-2 (ISBN)
Public defence
2013-09-27, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Available from: 2013-09-06 Created: 2013-08-15 Last updated: 2014-01-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Ramzan, MuhammadAhuja, Rajeev
By organisation
Materials Theory
In the same journal
Solid State Communications
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 209 hits
ReferencesLink to record
Permanent link

Direct link