Thesis defence by Damir PINEK

Shedding light on the electronic structure of Mn+1AXn nanolamellar carbides

keywords

Solid state physics, electronic structure, nanolamellar materials, crystal growth, angle resolved photoelectron spectroscopy, density functional theory, band structure, Fermi surface

cliquer pour voir la liste des membres du jury/clic here for the jury members

 



Abstract

The Mn+1AXn, or “MAX” phases, where M is an early transition metal, A belongs to group 13-16 of the periodic table and X is C or N, are a class of nano-layered compounds that have sparked a strong interest from the material science community for their unique combinations of metal-like and ceramic-like properties. They are also precursors for MXENES, a whole family of two dimensional carbides obtained by exfoliation of 3D MAX phases and notably sought for energy storage developments. Up to 155 MAX phases have been discovered up to now. Despite MAX phases’ attractiveness for a wide range of applications, the origins of several of their fundamental features are still under debate, notably regarding the relationships between their electronic structure, anisotropies and transport properties.
We present here the methodology we followed to grow MAX phase single crystals and experimentally determine the morphology of the electronic states (e.g. Band structure and Fermi surface) of Cr2AlC, V2AlC and Ti3SiC2. The output of angle resolved photoemission spectroscopy experiments carried out on single crystals are compared with density functional theory calculations. Band renormalization from electron-phonon coupling and influence of spin orbit coupling are outlined. The respective anisotropies of the Fermi surfaces are discussed with respect to the transport coefficients of each phase. The derivation of rigid band models that model the electronic structure of M2AC -or “211” MAX phases- is then developed. Finally, band structure and Fermi surface mappings of Ti2SnC and of MAX phases magnetic derivatives –iMAX and 4473 phases- are briefly introduced, as well as prospect of the potential exploration of (MxN1-x)2AX solid solutions for tuning the position of the Fermi level in order to reach topological nodes within the band structure of 211 MAX phases.


Membres du jury/ Jury members :
 

Prof.

V.Mauchamp

Institut PPrime, Université de Poitier, Poitier, France

Rapporteur

Dr.

A.Santander

Institut des Sciences Moléculaires d’Orsay, Université Paris-Saclay, Orsay, France

Rapporteur

Prof .

M.Barsoum

Material Science and Engineering department, Drexel University, Philadelphia, U.S.

Examiner

Assoc. Prof.

T.Ito

Synchrotron Radiation Research Center, Nagoya University, Nagoya, Japan

Examiner

Prof.

J-C.Charlier

Institute of Condensed-Matter and Nanoscience, Université Catholique de Louvain, Louvain-La-Neuve, Belgique

Examiner

Prof.

T.Ouisse

LMGP, Grenoble INP-Minatec, Grenoble France

Thesis Director

 

Date infos
2.30 p.m. - Salle des Conseils Z-704, 7th floor, Building Z (Grenoble INP Phelma building)
Location infos
Grenoble INP - Phelma
3 parvis Louis Néel - 38000 Grenoble
Accès : TRAM B arrêt Cité internationale
Free entrance - No registration