arXiv subjects

Luigi Maritato

Publications and source records attributed to Luigi Maritato.

5 recordsLinked to original sources

arXiv2026

Interfacial properties of MoS2 thin films grown on functional substrates

Interface chemistry and defect formation in MoS2 thin films grown on single crystal substrates critically determine the electronic structure of MoS2 and thus can strongly modify material functionality relevant for many applications, including electronics, optoelectronics, and energy related catalysis. We investigate MoS2 grown on three technologically relevant substrates, namely SrTiO3(111), c-axis Al2O3(0001) and 6H-SiC(0001). Experimental investigations by temperature dependent resistivity, photoemission spectroscopy and scanning transmission electron microscopy with coupled energy dispersive spectroscopy, with the support of theoretical calculation by Density Functional Theory, allow the identification of the substrate induced specific defects and their correlation with the electronic properties. Ti interdiffusion in SrTiO3/MoS2 generates donor like states near the Fermi level, leading to metallic transport. Al2O3/MoS2 exhibits a high density of sulfur related defects that introduce localized states and yield nearly temperature independent conductivity. SiC/MoS2 exhibits significant interface disorder resulting in a semiconducting temperature dependent resistivity, yet deviating from the ideal bulk like behavior. These results demonstrate how substrate choice governs defect formation and ultimately dominates the electronic behavior of MoS2 thin films, making the control of film substrate interactions essential for the engineering of new functional devices.

cond-mat.mtrl-sci↗

arXiv2026

Substrate induced optimization of the Electrocatalytic Hydrogen Evolution Reaction (HER) performances of MoS2 thin film

Molybdenum disulfide (MoS2) has emerged as a promising, cost-effective catalyst for hydrogen production via water splitting. We investigate the structural and electrocatalytic properties of MoS2 thin films deposited on different substrates (Al2O3, SiC, STO) to study their hydrogen evolution reaction (HER) activity. In particular, in order to study the substrate influence on the stabilization of different polymorphic MoS2 phases, the films are synthesised using pulsed laser deposition on substrates with different crystal symmetries and lattice parameters. All the deposited samples are characterized by X-Ray Diffraction, Raman Spectroscopy, Linear Sweep Voltammetry and Electrochemical Impedance Spectroscopy analyses. The films grown on Al2O3 substrates exhibit the best HER performance, likely due to the stabilization of the metastable 1T phase through the interfacial interactions between film and substrate. Presence of the 1T phase in the samples grown on Al2O3 improves the charge transfer efficiency and the electrochemically active surface with a better response to the applied potential, demonstrating their enhanced catalytic behaviour for hydrogen evolution.

cond-mat.mtrl-sci↗

arXiv2024

Temperature-induced hysteretic behavior of resistivity and magnetoresistance of electrodeposited bismuth films for X- ray transition-edge sensor absorbers

This study investigates the temperature-induced hysteretic behavior of resistivity and magnetoresistance in electrodeposited bismuth films, with a focus on their application as absorbers in transition-edge sensors (TESs) for X-ray detection. Through a series of resistance versus temperature measurements from room temperature to a few Kelvins, we explore the change in the conductive behavior of bismuth electrodeposited on various substrates at the various temperatures. Our findings show for the first time both hysteretic and irreversible changes in resistivity as a function of temperature. Further, magnetoresistance measurements reveal notable variations in resistance behavior under different magnetic fields, highlighting the impact of magnetic fields on these films' electronic transport properties, with an indication of potential weak anti-localization effects at the lowest temperatures. This study not only provides a deeper understanding of bismuth's conductivity characteristics at low temperatures but also sheds light on the practical implications for developing more effective TESs for synchrotron X-ray facilities.

physics.ins-det↗

arXiv2015

Doping evolution and polar surface reconstruction of the infinite-layer cuprate Sr$_{1-x}$La$_{x}$CuO$_{2}$

We use angle-resolved photoemission spectroscopy to study the doping evolution of infinite-layer Sr$_{1-x}$La$_{x}$CuO$_{2}$ thin films grown by molecular-beam epitaxy. At low doping, the material exhibits a dispersive lower Hubbard band typical of the superconducting cuprate parent compounds. As carriers are added to the system, a continuous evolution from charge-transfer insulator to superconductor is observed, with the initial lower Hubbard band pinned well below the Fermi level and the development of a coherent low-energy band with electron doping. This two-component spectral function emphasizes the important role that strong local correlations play even at relatively high doping levels. Electron diffraction probes reveal a ${p(2\times2)}$ surface reconstruction of the material at low doping levels. Using a number of simple assumptions, we develop a model of this reconstruction based on the polar nature of the infinite-layer structure. Finally, we provide evidence for a thickness-controlled transition in ultrathin films of SrCuO$_2$ grown on nonpolar SrTiO$_3$, highlighting the diverse structural changes that can occur in polar complex oxide thin films.

cond-mat.supr-con↗

arXiv2012

Nodeless superconductivity arising from strong (pi,pi) antiferromagnetism in the infinite-layer electron-doped cuprate Sr1-xLaxCuO2

The asymmetry between electron and hole doping remains one of the central issues in high-temperature cuprate superconductivity, but our understanding of the electron-doped cuprates has been hampered by apparent discrepancies between the only two known families: Re2-xCexCuO4 and A1-xLaxCuO2. Here we report in situ angle-resolved photoemission spectroscopy measurements of epitaxially-stabilized films of Sr1-xLaxCuO2 synthesized by oxide molecular-beam epitaxy. Our results reveal a strong coupling between electrons and (pi,pi) antiferromagnetism that induces a Fermi surface reconstruction which pushes the nodal states below the Fermi level. This removes the hole pocket near (pi/2,pi/2), realizing nodeless superconductivity without requiring a change in the symmetry of the order parameter and providing a universal understanding of all electron-doped cuprates.

cond-mat.supr-con↗