Rectification by Doped Mott-Insulator Junctions

TL;DR

This paper demonstrates that doped Mott-insulator junctions can achieve high-frequency rectification due to their strong electronic correlations and short electron-electron scattering times, surpassing traditional semiconductor limits.

Contribution

The study models Mott-insulator junctions using one-dimensional electron chains and shows their ability to rectify at frequencies beyond terahertz, using exact and DMRG numerical methods.

Findings

Short chains rectify charge with exact solutions.

Longer chains also exhibit rectification via DMRG.

Rectification occurs at frequencies higher than traditional semiconductors.

Abstract

Junctions of doped Mott insulators offer a route to rectification at frequencies beyond the terahertz range. Mott insulators have strong electronic correlations and therefore short timescales for electron-electron scattering. It is this short time scale that allows for the possibility of rectification at frequencies higher than those of semiconductor devices that are limited by the slow diffusion of charge carriers. We model a junction by a one dimensional chain of electrons with p- and n-doping on the two halves of the chain. Two types of systems are investigated: spin polarized electrons with nearest-neighbor interaction, and spin-half electrons that interact via on-site repulsion (the Hubbard model). For short chains the many-body Schrodinger equation can be integrated numerically exactly, and when driven by an oscillating electromagnetic field such idealized junctions rectify, showing a preferred direction for charge transfer. Longer chains are studied by the time-dependent density-matrix renormalization-group method, and also shown to rectify.