Mixed-Sandwich Titanium(III) Qubits on Au(111): Electron Delocalization Ruled by Molecular Packing

Abstract

Organometallic sandwich complexes are versatile molecular systems that have been recently employed for single-molecule manipulation and spin sensing experiments. Among related organometallic compounds, the mixed-sandwich S = 1/2 complex (η8-cyclooctatetraene)­(η5-cyclopentadienyl)­titanium, here [CpTi(cot)], has attracted interest as a spin qubit because of the long coherence time. Here the structural and chemical properties of [CpTi(cot)] on Au(111) are investigated at the monolayer level by experimental and computational methods. Scanning tunneling microscopy suggests that adsorption occurs in two molecular orientations, lying and standing, with a 3:1 ratio. XPS data evidence that a fraction of the molecules undergo partial electron transfer to gold, while our computational analysis suggests that only the standing molecules experience charge delocalization toward the surface. Such a phenomenon depends on intermolecular interactions that stabilize the molecular packing in the monolayer. This orientation-dependent molecule–surface hybridization opens exciting perspectives for selective control of the molecule–substrate spin delocalization in hybrid interfaces.

Chirality‐Induced Spin Selectivity: An Enabling Technology for Quantum Applications

“…ii) Quantum gates iii) Chemical engineering of the Hamiltonian [ 7,8,13,30] [ [20][21][22][23] [ 27,31] iv) Quantum algorithms v) Embedded quantum error correction vi) Processability and hybrid structures [28] [ 17, [32][33][34] [ [35][36][37][38][39][40][41][42][43][44] Each column refers to a different achievement/capability. In the different rows, we report the experimental results/schemes, the related molecular structures, and the relevant references.…”

“…[34] Copyright 2022, American Chemical Society). vi) Processability into hybrid structures and organization onto metallic and superconducting surfaces, [35][36][37][38][39][40] tuning their coupling with the substrate, while keeping their magnetic properties and enabling manipulation of electronic [41] and nuclear spins. [42] Color code for molecular structures: C gray; N pale blue, O red, S yellow, V purple, Cu orange, Ni and Cr blue, Tb cyan, lanthanides in (v) green and white.…”

“…perspectives for integration in quantum networks. [50,51] Finally, molecular spins can be processed into hybrid structures and organized on surfaces [35][36][37][38][39][40]43] or within superconducting resonators. [41,42,44] In this context, spin-correlated radical pairs (RPs) generated by photoinduced electron transfer (PET) have also been proposed for quantum information, because of their natural existence in entangled Bell states and the possibility of achieving atomic-scale control and interaction with other degrees of freedom, such as photons, charges and phonons.…”

“…[ 32–34,48,49 ] The ingenious design of the electronic structure has also enabled a promising step toward optical initialization and readout of molecular spin qubits with interesting perspectives for integration in quantum networks. [ 50,51 ] Finally, molecular spins can be processed into hybrid structures and organized on surfaces [ 35–40,43 ] or within superconducting resonators. [ 41,42,44 ]…”

A Combined Synthetic, Magnetic, and Theoretical Study on Enhancing Ligand-Field Axiality for Dy(III) Single-Molecule Magnets Supported by Ferrocene Diamide Ligands

“…Single-molecule magnets (SMMs) exhibiting slow magnetic relaxation have drawn great attention since the discovery of the Mn 12 cluster for their potential applications in ultrahigh-density information storage, − quantum computing, − and spintronics. , A high effective energy barrier ( U eff ) and high blocking temperature ( T B ) are crucial for the performance of SMMs. − Since lanthanide ions possess large unquenched angular momentum and high single-ion anisotropy, molecular lanthanide complexes are excellent candidates for developing high-performance SMMs. , As a Kramers ion with oblate 4f electron densities, dysprosium­(III) is highly desirable for designing lanthanide SMMs. − Most notably, a series of bis­(cyclopentadienyl) dysprosium­(III) complexes showed groundbreaking SMM properties. − All these dysprosium­(III) complexes feature a close to linear coordination geometry around the dysprosium­(III) ion with the best performer [(Cp i Pr5 )­Dy­(Cp*)]­[B­(C 6 F 5 ) 4 ] (Cp i Pr5 = η 5 -C 5 i Pr 5 , Cp* = η 5 -C 5 Me 5 ) exhibiting a U eff of 2217 K and a T B of 80 K …”