A5014483105- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Nanowire Synthesis and Applications
- Graphene research and applications
- Semiconductor Quantum Structures and Devices
- Physics of Superconductivity and Magnetism
- Semiconductor materials and devices
- Advanced Thermoelectric Materials and Devices
- 2D Materials and Applications
- Topological Materials and Phenomena
- Thermal properties of materials
- Surface and Thin Film Phenomena
- Electronic and Structural Properties of Oxides
- Thermal Radiation and Cooling Technologies
- Quantum Information and Cryptography
- Molecular Junctions and Nanostructures
- Diamond and Carbon-based Materials Research
- Mechanical and Optical Resonators
- Semiconductor materials and interfaces
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Sensor and Energy Harvesting Materials
- Carbon Nanotubes in Composites
- Photonic and Optical Devices
- Electron and X-Ray Spectroscopy Techniques
- Quantum Dots Synthesis And Properties
Istituto Nanoscienze
2015-2025
University of Pisa
2018-2025
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2019-2025
Scuola Normale Superiore
2014-2023
National Enterprise for NanoScience and NanoTechnology
2007-2023
Moscow Institute of Physics and Technology
2020
Princeton University
2012-2020
National Research University Higher School of Economics
2020
Osipyan Institute of Solid State Physics RAS
2020
Russian Quantum Center
2020
Abstract In the emergent field of quantum technology, ability to manage heat at nanoscale and in cryogenic conditions is crucial for enhancing device performance terms noise, coherence, sensitivity. Here, active cooling refrigeration electron gas graphene are demonstrated, by taking advantage superconducting tunnel contacts able pump or extract directly from electrons device. These structures achieved a top ∼15.5 mK bath temperature ∼448 mK, demonstrating viability proposed architecture....
Monatomic layers of graphite are emerging as building blocks for novel optoelectronic devices. Experimental studies on a single layer (graphene) today possible since very thin can be identified dielectric substrate using normal optical microscope. We investigate the mechanism behind strong visibility graphite, and we discuss importance substrates microscope objective used imaging.
The adoption of graphene in electronics, optoelectronics, and photonics is hindered by the difficulty obtaining high-quality material on technologically relevant substrates, over wafer-scale sizes, with metal contamination levels compatible industrial requirements. To date, direct growth insulating substrates has proved to be challenging, usually requiring metal-catalysts or yielding defective graphene. In this work, a metal-free approach implemented commercially available reactors obtain...
We report the Au-assisted chemical beam epitaxy growth of defect-free zincblende InSb nanowires. The grown segments are upper sections InAs/InSb heterostructures on InAs(111)B substrates. show, through HRTEM analysis, that can be without any crystal defects such as stacking faults or twinning planes. Strain-map analysis demonstrates segment is nearly relaxed within a few nanometers from interface. By post-growth studies we have found catalyst particle composition AuIn(2), and it varied to...
We demonstrate high-temperature thermoelectric conversion in InAs/InP nanowire quantum dots by taking advantage of their strong electronic confinement. The electrical conductance G and the thermopower S are obtained from charge transport measurements accurately reproduced with a theoretical model accounting for multilevel structure dot. Notably, our analysis does not rely on estimate cotunnelling contributions, since thermal is dominated heat transport. By into account two spin-degenerate...
CMOS-compatible materials for efficient energy harvesters at temperatures characteristic on-chip operation and body temperature are the key ingredients sustainable green computing ultralow power Internet of Things applications. In this context, lattice thermal conductivity (κ) new group IV semiconductors, namely Ge1–xSnx alloys, investigated. Layers featuring Sn contents up to 14 at.% epitaxially grown by state-of-the-art chemical-vapor deposition on Ge buffered Si wafers. An abrupt decrease...
We present a capacitance-voltage study for arrays of vertical InAs nanowires. Metal-oxide-semiconductor (MOS) capacitors are obtained by insulating the nanowires with conformal 10nm HfO2 layer and using top Cr∕Au metallization as one capacitor’s electrodes. The described fabrication characterization technique enables systematic investigation carrier density in well quality MOS interface.
We investigate tunable hole quantum dots defined by surface gating $\mathrm{Ge}/\mathrm{Si}$ core-shell nanowire heterostructures. In single level Coulomb-blockade transport measurements at low temperatures spin doublets are found, which become sequentially filled holes. Magnetotransport allow us to extract a $g$ factor ${g}^{*}\ensuremath{\approx}2$ close the value of free spin-$1/2$ particle in case smallest dot. less confined smaller values observed. This indicates lifting expected strong...
Millivolt range thermovoltage is demonstrated in single InAs-nanowire based field effect transistors. Thanks to a buried heating scheme, we drive both large thermal bias DT>10K and strong field-effect modulation of electric conductance on the nanostructures. This allows precise mapping evolution Seebeck coefficient S as function gate-controlled conductivity between room temperature 100K$. Based these experimental data novel estimate electron mobility given. value compared with result...
The Josephson effect is a fundamental quantum phenomenon consisting in the appearance of dissipationless supercurrent weak link between two superconducting (S) electrodes. While mechanism leading to quite general, i.e., Andreev reflections at interface S electrodes and link, precise physical details topology junction drastically modify properties supercurrent. Specifically, strong enhancement critical $I_C$ expected occur when allows emergence Majorana bound states. Here we report charge...
We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV graphene, study how low-energy carriers interact lattice vibrations. Thanks the close Dirac point at K, we unveil a giant increase of intensity ratio between double-resonant 2D and 2D′ peaks respect that measured in graphite. Comparing fully ab initio theoretical calculations, conclude observation is explained by an enhanced, momentum-dependent coupling electrons Brillouin zone-boundary...
We introduce and experimentally demonstrate a new method that allows us to controllably couple copropagating spin-resolved edge states of two-dimensional electron gas (2DEG) in the integer quantum Hall regime. The scheme exploits spatially periodic in-plane magnetic field is created by an array Cobalt nanomagnets placed at boundary 2DEG. A maximum charge or spin transfer $28\ifmmode\pm\else\textpm\fi{}1%$ achieved 250 mK.
Semiconductor nanowires featuring strong spin–orbit interactions (SOI), represent a promising platform for broad range of novel technologies, such as spintronic applications or topological quantum computation. However, experimental studies into the nature and orientation SOI vector in these wires remain limited despite being upmost importance. Typical devices feature placed on top substrate which modifies spoils intrinsic symmetries system. In this work, we report results suspended InAs...
We have studied mesoscopic Josephson junctions formed by highly $n$-doped InAs nanowires and superconducting Ti/Pb source drain leads. The current-voltage properties of the system are investigated varying temperature external out-of-plane magnetic field. Superconductivity in Pb electrodes persists up to $ \sim 7$ K with field values 0.4 T. coupling at zero backgate voltage is observed 4.5 critical current measured be as high 615 nA. supercurrent suppression a function reveals diffraction...
Recent experiments have shown the possibility of tuning transport properties metallic nanosized superconductors through a gate voltage. These results renewed longstanding debate on interaction between electrostatic fields and superconductivity. Indeed, different works suggested competing mechanisms as cause effect: an unconventional electric field-effect or quasiparticle injection. Here, we provide conclusive evidence for electrostatic-field-driven control supercurrent in superconductors, by...
We present a novel technique for the manipulation of energy spectrum hard-wall InAs/InP nanowire quantum dots. By using two local gate electrodes, we induce strong transverse electric field in dot and demonstrate controlled modification its electronic orbitals. Our approach allows us to dramatically enhance single-particle spacing between first levels thus increment working temperature our single-electron transistors. devices display very robust modulation conductance even at liquid nitrogen...
The control and measurement of local non-equilibrium configurations is utmost importance in applications on energy harvesting, thermoelectrics heat management nano-electronics. This challenging task can be achieved with the help various probes, prominent examples including superconducting or quantum dot based tunnel junctions, classical resistors, Raman thermography. Beyond time-averaged properties, valuable information also gained from spontaneous fluctuations current (noise). From these...
Generation of ultra high frequency acoustic waves in water is key to nano resolution sensing, imaging and theranostics. In this context immersed carbon nanotubes (CNTs) may act as an ideal optoacoustic source, due their nanometric radial dimensions, peculiar thermal properties broad band optical absorption. The generation mechanism water, upon excitation both a single-wall (SW) multi-wall (MW) CNT with laser pulses temporal width ranging from 5 ns down ps, theoretically investigated via...
Abstract Hydrogen (H) plays a key role in the near-to-room temperature superconductivity of hydrides at megabar pressures. This suggests that H doping could have similar effects on electronic and phononic spectra materials ambient pressure as well. Here, we demonstrate non-volatile control ground state titanium diselenide (1 T -TiSe 2 ) via ionic liquid gating-driven intercalation. protonation induces superconducting phase, observed together with charge-density wave through most phase...