Anisotropy of the resistivity and charge-carrier sign in nanolaminated Ti2AlC: Experiment and ab initio calculations
2013 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 87, no 23Article in journal (Refereed) Published
The anisotropy of Ti2AlC transport properties is investigated focusing on the Hall effect and resistivity vs temperature measurements performed on a highly (000l)-oriented thin film and a bulk polycrystalline sample. Experimental data are interpreted on the basis of density functional theory calculations including transport coefficients obtained with the Boltzmann semiclassical transport equation in the isotropic relaxation time approximation. It is shown that the Hall constant is independent of the temperature and that the charge-carrier sign depends on the investigated crystallographic orientation. Charge carriers exhibit a holelike character along the basal plane of the Ti2AlC, whereas the bulk sample Hall constant is negative. The resistivity anisotropy is also evidenced: using an effective medium approach, the room temperature basal plane resistivity is shown to be more than one order of magnitude lower than that along the c axis. This very important anisotropy is shown to result from the anisotropy of the Fermi surface increased by electron-phonon interactions. These interactions are much more important along the c axis than within the basal plane, a situation opposite to that observed in literature for Ti2GeC where resistivity was reported to be isotropic.
Place, publisher, year, edition, pages
American Physical Society , 2013. Vol. 87, no 23
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-96470DOI: 10.1103/PhysRevB.87.235105ISI: 000320103900001OAI: oai:DiVA.org:liu-96470DiVA: diva2:642920