Suppression of rectification at metal-Mott-insulator interfaces
Abstract
Charge transport through metal-Mott-insulator interfaces is studied and compared with that through metal-band-insulator interfaces. For band insulators, rectification has been known to occur owing to a Schottky barrier, which is produced by the work-function difference. For Mott insulators, however, qualitatively different current-voltage characteristics are obtained. Theoretically, we use the one-dimensional Hubbard model for a Mott insulator and attach to it the tight-binding model for metallic electrodes. A Schottky barrier is introduced by a solution to the Poisson equation with a simplified density-potential relation. The current density is calculated by solving the time-dependent Schr\"odinger equation. We mainly use the time-dependent Hartree-Fock approximation, and also use exact many-electron wave functions on small systems for comparison. Rectification is found to be strongly suppressed even for large work-function differences. We show its close relationship with the fact that field-effect injections into one-dimensional Mott insulators are ambipolar. Experimentally, we fabricated asymmetric contacts on top of single crystals of quasi-one-dimensional organic Mott and band insulators. Rectification is strongly suppressed at an interface between metallic magnesium and Mott-insulating (BEDT-TTF)(FTCNQ) [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene, FTCNQ=2,5-difluorotetracyanoquinodimethane].
Cite
@article{arxiv.0710.5586,
title = {Suppression of rectification at metal-Mott-insulator interfaces},
author = {Kenji Yonemitsu and Nobuya Maeshima and Tatsuo Hasegawa},
journal= {arXiv preprint arXiv:0710.5586},
year = {2009}
}
Comments
6 pages, 5 figures, accepted for publication in Phys. Rev. B