Self‐Cooling Molecular Spin Qudits
Abstract
Abstract The need of operating molecular spin qubits at very low temperatures constitutes a technological limitation. This challenge is addressed by integrating, in the same material and at the molecular scale, quantum processing and magnetic refrigeration capabilities. The molecular unit is a [GdEr] heterolanthanide coordination complex, where Er(III) encodes a qubit while Gd(III) provides a large magnetocaloric effect. The properties of each component are separately studied in isostructural [LaEr] and [GdLu] complexes, where each functional ion lies next to a diamagnetic metal. All complexes are characterized by magnetic, heat capacity, and EPR measurements. The results show that the presence of both ions in the same molecule has a synergic effect on both functionalities. Thus, the coupling between Er(III) and Gd(III) spins lifts any level degeneracies even close to zero magnetic field, leading to a d = 16 set of spin states that, as revealed by pulse EPR measurements, can be coherently manipulated. In turn, Er(III) enhances the magnetocaloric effect compared to [GdLu], extending it to lower temperatures. This is corroborated by direct magnetocaloric measurements, which show the ability of this material to cool itself, and a device, down to temperatures as low as 0.4 K.
Article Details
Authors (13)
Elias Palacios
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC & Universidad de Zaragoza
David Aguilà
Departament de Química Inorgànica i Orgànica, and IN2UB Universitat de Barcelona Diagonal 645 Barcelona 08028 Spain
David Gracia
Instituto de Nanociencia y Materiales de Aragón (INMA)
Diamatoula Maniaki
Departament de Química Inorgànica i Orgànica, and IN2UB Universitat de Barcelona Diagonal 645 Barcelona 08028 Spain
Leoní A. Barrios
Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 Barcelona 08028 Spain
Alessandro Chiesa
Department of Mathematical, Physical and Computer Sciences
Jesús I. Martínez
Instituto de Nanociencia y Materiales de Aragón (INMA) CSIC‐Universidad de Zaragoza and Departamento de Física de la Materia Condensada Universidad de Zaragoza Zaragoza 50009 Spain
Valentin Novikov
Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 Barcelona 08028 Spain
Olivier Roubeau
Instituto de Nanociencia y Materiales de Aragón (INMA) CSIC and Universidad de Zaragoza Plaza San Francisco s/n Zaragoza 50009 Spain
Stefano Carretta
Department of Mathematical, Physical and Computer Sciences
Marco Evangelisti
Instituto de Nanociencia y Materiales de Aragón (INMA)
Guillem Aromí
Departament de Química Inorgànica i Orgànica Universitat de Barcelona Diagonal 645 Barcelona 08028 Spain
Fernando Luis
Instituto de Nanociencia y Materiales de Aragón (INMA) CSIC‐Universidad de Zaragoza and Departamento de Física de la Materia Condensada Universidad de Zaragoza Zaragoza 50009 Spain