0000000000350406
AUTHOR
Antonio Vecchione
showing 5 related works from this author
Current driven insulator-to-metal transition without Mott breakdown in Ca$_2$RuO$_4$
2023
The electrical control of a material's conductivity is at the heart of modern electronics. Conventionally, this control is achieved by tuning the density of mobile charge carriers. A completely different approach is possible in Mott insulators such as Ca$_2$RuO$_4$, where an insulator-to-metal transition (IMT) can be induced by a weak electric field or current. This phenomenon has numerous potential applications in, e.g., neuromorphic computing. While the driving force of the IMT is poorly understood, it has been thought to be a breakdown of the Mott state. Using in operando angle-resolved photoemission spectroscopy, we show that this is not the case: The current-driven conductive phase ari…
Anomalous orbital moment in the ferromagnetic phase of the Sr4Ru3O10
2018
The coupling of spin and orbital degrees of freedom in the trilayer Sr4Ru3O10 sets a long-standing puzzle, due to the peculiar anisotropic coexistence of out-of-plane ferromagnetism and in-plane metamagnetism. Recently, the induced magnetic structure by in-plane applied fields has been investigated by means of spin-polarized neutron diffraction, which allowed to extract a substantial orbital component of the magnetic densities at Ru sites. It has been argued that the latter is at the origin of the evident layer dependent magnetic anisotropy, where the inner layers carry larger magnetic moments than the outer ones. We present a spin-polarized neutron diffraction study in order to characteriz…
Quantum phase slips in superconducting Nb nanowire networks deposited on self-assembled Si templates
2012
Robust porous silicon substrates were employed for generating interconnected networks of superconducting ultrathin Nb nanowires. Scanning electron microscopy analysis was performed to investigate the morphology of the samples, which constitute of polycrystalline single wires with grain size of about 10 nm. The samples exhibit nonzero resistance over a broad temperature range below the critical temperature, fingerprint of phase slippage processes. The transport data are satisfactory reproduced by models describing both thermal and quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires.
Emergence of a metallic metastable phase induced by electrical current in Ca2RuO4
2019
A comprehensive study of the behavior of the Mott insulator ${\mathrm{Ca}}_{2}{\mathrm{RuO}}_{4}$ under electrical current drive is performed by combining two experimental probes: the macroscopic electrical transport and the microscopic x-ray diffraction. The resistivity, $\ensuremath{\rho}$, versus electric current density, $J$, and temperature, $T,\ensuremath{\rho}(J,T)$, resistivity map is drawn. In particular, the metastable state, induced between the insulating and the metallic thermodynamic states by current biasing ${\mathrm{Ca}}_{2}{\mathrm{RuO}}_{4}$ single crystals, is investigated. Such an analysis, combined with the study of the resulting ${\mathrm{RuO}}_{6}$ octahedra energy le…
Comparative study of initial stages of copper immersion deposition on bulk and porous silicon
2013
Initial stages of Cu immersion deposition in the presence of hydrofluoric acid on bulk and porous silicon were studied. Cu was found to deposit both on bulk and porous silicon as a layer of nanoparticles which grew according to the Volmer-Weber mechanism. It was revealed that at the initial stages of immersion deposition, Cu nanoparticles consisted of crystals with a maximum size of 10 nm and inherited the orientation of the original silicon substrate. Deposited Cu nanoparticles were found to be partially oxidized to Cu2O while CuO was not detected for all samples. In contrast to porous silicon, the crystal orientation of the original silicon substrate significantly affected the sizes, dens…