Role of vibrations on decoherence in molecular spin qubits: The case of [Cu(mnt)$_2$]$^{2-}$

TL;DR

This paper presents a first-principles method to analyze how vibrations affect spin energy levels in molecular qubits, demonstrated on a coherent copper complex, aiding the design of more resilient magnetic molecules.

Contribution

It introduces a simple first-principles approach to quantify vibrational effects on spin levels, guiding the design of high-temperature molecular spin qubits.

Findings

Identified key vibrational modes affecting spin coherence.

Proposed strategies for designing vibration-resilient magnetic molecules.

Applied methodology successfully to a highly coherent copper complex.

Abstract

Herein we develop a simple first-principles methodology to determine the modulation that vibrations exert on spin energy levels, a key for the rational design of high-temperature molecular spin qubits and single-molecule magnets. This methodology is demonstrated by applying it to [Cu(mnt)$_2$]$^{2-}$ (mnt$^{2-}$ = 1,2-dicyanoethylene-1,2-dithiolate), a highly coherent complex, using DFT to calculate the normal vibrational modes and wave-function based theory calculations to estimate the spin energy level structure. By theoretically identifying the most relevant vibrational modes, we are able to offer general strategies to chemically design more resilient magnetic molecules, where the qubit energy is not coupled to local vibrations.