arXiv subjects

Lorena E. Rosaleny

Publications and source records attributed to Lorena E. Rosaleny.

5 recordsLinked to original sources

arXiv2023

Lanthanide molecular nanomagnets as probabilistic bits

Over the decades, the spin dynamics of a large set of lanthanide complexes have been explored. Lanthanide-based molecular nanomagnets are bistable spin systems, generally conceptualized as classical bits, but many lanthanide complexes have also been presented as candidate quantum bits (qubits). Here we offer a third alternative and model them as probabilistic bits (p-bits), where their stochastic behavior constitutes a computational resource instead of a limitation. We present a modelling tool for molecular spin p-bits, we demonstrate its capability to simulate bulk magnetic relaxation data and ac experiments and to simulate a minimal p-bit network under realistic conditions. Finally, we go back to a recent systematic data gathering and screen the best lanthanide complexes for p-bit behavior, lay out the performance of the different lanthanide ions and chemical families and offer some chemical design considerations.

cond-mat.mes-hall↗

arXiv2022

Data mining, dashboard and statistical analysis: a powerful framework for the chemical design of molecular nanomagnets

Three decades of research in molecular nanomagnets have raised their magnetic memories from liquid helium to liquid nitrogen temperature thanks to a wise choice of the magnetic ion and coordination environment. Still, serendipity and chemical intuition played a main role. In order to establish a powerful framework for statistically driven chemical design, we collected chemical and physical data for lanthanide-based nanomagnets, catalogued over 1400 published experiments, developed an interactive dashboard (SIMDAVIS) to visualise the dataset, and applied inferential statistical analysis. Our analysis showed that the Arrhenius energy barrier correlates unexpectedly well with the magnetic memory, as both Orbach and Raman processes can be controlled by vibronic coupling. Indeed, only bis-phthalocyaninato sandwiches and metallocenes, with rigid ligands, consistently present magnetic memory up to high temperature. Analysing magnetostructural correlations, we offer promising strategies for improvement, in particular for the preparation of pentagonal bipyramids, where even "softer" complexes are protected against molecular vibrations.

cond-mat.mes-hall↗

arXiv2020

Reinforced Room temperature spin filtering in chiral paramagnetic metallopeptides

Chiral-induced spin selectivity (CISS), whereby helical molecules polarize the spin of electrical current, is an intriguing effect with potential applications in nanospintronics. In this nascent field, the study of paramagnetic chiral molecules, which could introduce another degree of freedom in the control of the spin transport, remains so far unexplored. To address this challenge, herein, we propose the use of self-assembled monolayers of helical lanthanide-binding peptides. In order to elucidate the effect of the paramagnetic nuclei, monolayers of the peptide coordinating paramagnetic or diamagnetic ions are prepared. By means of spin-dependent electrochemistry, CISS effect is demonstrated by cyclic voltammetry and impedance measurements for both samples. Additionally, an implementation of the standard liquid-metal drop electron transport setup has been carried out, demonstrating their suitability for solid-state devices. Remarkably, the inclusion of a paramagnetic center in the peptide increases the spin polarization as independently proved by different techniques. These findings permit the inclusion of magnetic biomolecules in the CISS field, paving the way to their implementation in a new generation of spintronic nanodevices.

physics.app-ph↗

arXiv2018

Sub-picosecond molecular dynamics modulate the energies of spin states for hundreds of nanoseconds

Molecular vibrations are increasingly seen as a key factor for spin dynamics in single-ion magnets and molecular spin qubits. Herein we show how an inexpensive combination of molecular dynamics calculations and a crystal field analysis can be employed to obtain a dynamical picture of the crystal field splitting. We present the time evolution during 500ns of the spin energy levels in a terbium complex. Our calculations evidence an amplitude of up to tens of cm-1 for the oscillations of the spin energy levels in the fs time scale. Crucially, we also see that the oscillations average out and practically disappear at longer time scales, thus ruling out the modulation of spin energy levels by phonons of long wavelength $λ$ (up to $λ$ = 40 $Å$). Our results are compatible with the common approximation of focusing on local vibrations, but at the same time highlight the risks of assuming that the spin energy levels are time- and temperature-independent.

cond-mat.mes-hall↗

arXiv2017

Peptides as versatile scaffolds for quantum computing

In this work we showcase the potential of peptides as versatile scaffolds for quantum computing and molecular spintronics. In particular, we focus on lanthanide-binding tags, which were originally developed in the field of biotechnology for the study of protein structure and dynamics. Firstly, we demonstrate quantum coherent oscillations in a Neodymium peptidic qubit. Then, employing bacterial biosynthesis, we investigate the possibility of increasing the number of qubits in the same molecular system, with the case studies being a double spin qubit with two distinct coordination environments, and an asymmetric chain of 9 spin qubits with a spin-spin separation of about 2 nm and in an arbitrarily chosen sequence of coordination environments. Finally, we take advantage of biochemical modification for the preparation of paramagnetic, chiral, Self-Assembled Monolayers (SAMs) on Au(111).Our experimental and theoretical characterization shows that this is a promising structure for spintronic applications, and in particular to improve on two state-of-the-art approaches to molecular spin qubits. We conclude with an overview of the challenges and new opportunities opened by this emerging field.

cond-mat.mes-hall↗