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Prof. Dr. Ilaria Zardo

Department of Physics
Profiles & Affiliations

Nanophononics Lab

Our research focus lies in Nanophononics: the design and manipulation of the phononic properties of materials at the nanoscale. To reach this goal, we work on the development of novel materials as well as on the development of novel measurements platforms and the further advancement of existing experimental techniques. In particular, we probe the lattice dynamics and thermal transport of nanomaterials by means of inelastic light scattering and the by means of thermal conductivity measurements often combined with scanning thermometry. This approach enables us to elaborate 

new materials and innovative solutions for small sensors and energy harvesting.

Furthermore, we are particularly interested in the growth of nanowires and heterostructures based on Silicon and Germanium, both for nanophononics purposes as well as for the realization of spin qubits.


Selected Publications

de Vito, G., Koch, D.M., Raciti, G., Sojo-Gordillo, J.M., Nigro, A., Swami, R., Kaur, Y., Swinkels, M.Y., Huang, W., Paul, T., Calame, M., & Zardo, I. (2024). Suspended micro thermometer for anisotropic thermal transport measurements. International Journal of Heat and Mass Transfer, 224. https://doi.org/10.1016/j.ijheatmasstransfer.2024.125302

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K. Sivan, Aswathi, Abad, Begoña, Albrigi, Tommaso, Arif, Omer, Trautvetter, Johannes, Ruiz Caridad, Alicia, Arya, Chaitanya, Zannier, Valentina, Sorba, Lucia, Rurali, Riccardo, & Zardo, Ilaria. (2023). GaAs/GaP Superlattice Nanowires for Tailoring Phononic Properties at the Nanoscale: Implications for Thermal Engineering. ACS Applied Nano Materials, 6(19), 18602–18613. https://doi.org/10.1021/acsanm.3c04245

URLs
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De Luca, Marta, Fasolato, Claudia, Verheijen, Marcel A., Ren, Yizhen, Swinkels, Milo Y., Kölling, Sebastian, Bakkers, Erik P. A. M., Rurali, Riccardo, Cartoixà, Xavier, & Zardo, Ilaria. (2019). Phonon Engineering in Twinning Superlattice Nanowires. Nano letters, 19(7), 4702–4711. https://doi.org/10.1021/acs.nanolett.9b01775

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Selected Projects & Collaborations

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Hydronics

Research Project  | 1 Project Members

Hydrodynamic transport of heat or charge in solids is an exotic phenomenon, discovered more than 50 years ago for the case of coherent thermal transport ("second sound"), that has gained much prominence recently, due to its prediction and experimental observation in low-dimensional materials and nanostructures. While in most materials internal scattering processes lead to diffusive transport, pronounced anisotropy, low-dimensionality, or reduced temperatures can lead to hydrodynamic transport. These include coherent propagation of transport excitations, vortices in the viscous hydrodynamic transport, peculiar dependence on temperature or magnetic field, friction, slip and super-linear dependence of conductance as a function of width. Recent observations of hydrodynamic effects in 2D materials (graphene or 2DEGs) and in anisotropic 3D materials (PdCoO, SrTiO 3 , WP 2 ) for both charge and heat are striking, deserve extensive microscopic understanding, and can lead to engineering novel devices. There are major open key questions addressed in this proposal: i. Theory and simulation : Several hydrodynamic transport regimes have been posited - from second sound and coherent transport waves to friction effects in nanostructures. Viscosities can now be predicted and provide a bridge between Boltzmann transport and Navier-Stokes hydrodynamics. ii. Materials science : To reach the hydrodynamic regime materials will have to be cleanly fabricated. There is no sufficient understanding of the role of defects or of the influence of substrates and boundaries on the emergence of the hydrodynamic regime. iii. Experimental physics : Certain hydrodynamic signatures are yet to be confirmed experimentally, others have been shown only once and need to be reproduced. Oftentimes, evidence of hydrodynamic transport has to be based on several different effects to be conclusive. Further, clean demonstrations need to be developed for the measurement of heat, which pose well-known methodological challenges. iv. Device engineering : Materials, for which a hydrodynamic transport regime is expected, often fall into the realm of future device applications for other reasons ( e.g. , topological protection, high electronic mobility, optoelectronic properties). It is unclear how future, scaled devices will either suffer from hydrodynamics, or can even exploit hydrodynamic transport for device functionality. These research questions motivate a synergetic approach combining these four areas of science by partnering of four research groups with leading expertise in all these areas. Furthermore, it is proposed to combine the study of hydrodynamic effects in both heat and charge transport to exploit obvious synergies, such as the important role of electron-phonon scattering. The project will create a theoretical framework to extract hydrodynamic parameters ( e.g. the viscosity of a phonon system) from first principles. Materials will be grown and patterned to explore the limitations of designable hydrodynamic systems. Then, materials will be designed by layering and patterning of geometries to control hydrodynamic effects. Experiments will measure second-sound (pump-probe laser spectroscopy), non-local dissipation (scanning thermal microscopy), and quantify thermal, electrical and thermoelectric conductance and magnetoconductance of samples as a function of their dimensions. Finally, basic functional demonstration using 2-terminal and 3-terminal devices will be made showing rectification and drag-effects for heat and charge pumps.

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PHONUIT

Research Project  | 1 Project Members

In the last decades, the power to control photons and electrons paved the way for extraordinary technological developments in electronic and optoelectronic applications. The same degree of control is still lacking with quantized lattice vibrations, i.e. phonons. Phonons are the carriers of heat and sound. The understanding and ability to manipulate phonons as quantum particles in solids enable the control of coherent phonon transport, which is of fundamental interest and could also be exploited in applications. Logic operations can be realized with the manipulation of phonons both in their coherent and incoherent form in order to switch, amplify, and route signals, and to store information. If brought to a mature level, phononic devices can become complementary to the conventional electronics, opening new opportunities. I envision to realize each part of this technology exploiting phonons and to bring them together in an integrated circuit on chip: a phononic integrated circuit. The objective of the proposal is: A: the realization of coherent phonon source and detector; B: the realization of phonon computation with the use of thermal logic gates; C: the realization of phonon based quantum and thermal memories. To this end it is crucial to engineer nanoscale heterostructures with suitable interfaces, and to engineer the phonon spectrum and the interface thermal resistance. Phonons will be launched, probed and manipulated with a combination of pump-probe experiments and resistive thermal measurements on chip. The proposed research will be of great relevance for fundamental research as well as for technological applications in the field of sound and thermal management.