Linear and nonlinear Stark effect in triangular molecule

TL;DR

This paper investigates the Stark effect in a triangular molecule, revealing anisotropic linear and nonlinear responses, deriving exchange couplings for correlated electrons, and analyzing transport properties in coupled quantum dots.

Contribution

It provides a detailed analysis of the Stark effect in triangular molecules, including derivation of exchange couplings and transport behavior under electric fields.

Findings

Stark effect is anisotropic with linear and nonlinear components.

Identification of a dark spin state decoupled from others.

Transport properties are anisotropic and depend on electric field strength.

Abstract

We analyze changes of the electronic structure of a triangular molecule under the influence of an electric field (i.e., the Stark effect). The effects of the field are shown to be anisotropic and include both a linear and a nonlinear part. For strong electron correlations, we explicitly derive exchange couplings in an effective spin Hamiltonian. For some conditions one can find a dark spin state, for which one of the spins is decoupled from the others. The model is also applied for studying electronic transport through a system of three coherently coupled quantum dots. Since electron transfer rates are anisotropic, the current characteristics are anisotropic as well, differing for small and large electric field.