TiN/AlN and NbN/AlN superlattices: Integrating ferroelectricity and superconductivity
ORAL
Abstract
We investigate the electronic band structure, phonon dispersion, and electron-phonon interaction of TiN, δ-NbN, and their counterparts, i.e., Ti(Nb)N/AlN superlattice employing ab initio calculations. While TiN and δ-NbN have been known for their superconductivity, their integration with ferroelectric material is less known and explored here. We find the transition temperature (Tc) calculated for TiN is over 4.5 K which is close to experimental value (ranges in 4.8-5.25 K) while for NbN the value is more than 20 K that agrees well with experimental value (17.3 K). The higher Tc for δ-NbN comes from the stronger electron phonon coupling (λ) than TiN. The stacking of AlN on TiN and δ-NbN introduces ferroelectricity into these systems and changes the Tc . For TiN/AlN superlattice, Tc is around 6 K while for NbN/AlN superlattice it is around 20 K, the higher Tc likely comes from the Nb-d orbital electrons contributing to the flat band around the fermi level.
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Publication: A paper is planned that would have the same title. I hope it will be submitted for publication by the time I talk in March about it.
Presenters
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Huma Nawaz
- University of Houston