Phononic and Photonic Nanostructures

Group Leader: Clivia M. Sotomayor Torres

Main Research Lines

  • Nanophononics and nanophotonics

  • Nanoscale thermal transport

  • 2D materials

  • Optomechanics

  • Nanofabrication

  • Nanometrology

  • Oxide-based nanostructures

  • Radiative Cooling

During 2021, the group worked on four EU Horizon 2020 projects:

LEIT, Lossless Information for Emerging Information Technologies, ERC, AdG.

NANOPOLY, Artificial permittivity and permeability engineering for future generation sub wavelength analogue integrated circuits and systems, FET Open project.

TOCHA, Dissipationless topological channels for information transfer and quantum metrology, FET Proactive project.

NANOSMART, NANO components for electronic SMART wireless Systems, ICT project.

The group was also involved in two Spanish National Plan projects —namely, SIP (Surface and interface reshaped phonon propagation and phonon coupling to photons) and SMOOTH (Optomechanical devices based on self-assembled and active materials), with Dr P. D. Garcia as PI—, a regional project SGR, and a project funded by the ICN2 Severo Ochoa Technology and Valorisation programme on Cooling Photonics, coordinated by Dr J. Jaramillo. In 2021, the group made strong progress in radiative cooling, the findings of which went on to underpin the technological and scientific basis of the spin off Cooling Photonics S.L.

The Phononic and Photonic Nanostructures group achieved important research results during 2021, an overview of which is given below.

Regarding topological bosons, we proposed a measure of robustness for the protected states — namely, the group index— and simulated it in silicon waveguides.
We designed, fabricated and characterised crystalline and nano-crystalline Si-membrane based topologically protected phonons waveguides operating in the hypersound and observed a mechanical gap and guided gap modes in the GHz regime.

The mechanical properties of homogeneous 2D materials and their structural integrity were investigated applying strain around the critical values. The impact of this work is in the field of flexible devices based on MoS2. We have also studied the effect of polycrystallinity and interlayer stacking in the mechanical properties of 2D materials.

Thermal transport in homogeneous, polycrystalline, bilayers and heterostructures of 2D materials has been a hot topic in 2021 focusing on the role of interfaces in the thermal transport and the implications for energy harvesting and heat guiding. Our work earned us an invitation to write Heat transport control and thermal characterization of low-dimensional materials: A Review, which appeared in Nanomaterials.

Progressing in phonon engineering, phononic crystal structures supporting supersonic bound states in the hypersound were designed and studied experimentally, proving obstructed leakage.

Our research in optomechanics reached new heights with the demonstration of injection locking in an optomechanical coherent phonon source and the realisation of a phononic circuit platform operating at room temperature and based entirely on silicon technology. We demonstrated the electro-mechanical generation of phonons, the interaction of THz photons with GHz phonons and successfully transduced 2GHz signals, in a world first.

Group Leader

ICREA Research Prof. Dr Clivia M. Sotomayor Torres, leader of the ICN2 group Phononic and Photonic Nanostructures

Clivia M. Sotomayor Torres

ICREA Research Professor

ICREA Research Prof. Dr Clivia M. Sotomayor Torres was awarded her PhD in physics in 1984 by the University of Manchester (UK). She then held tenured academic appointments at the University of St. Andrews and the University of Glasgow in the UK, before becoming a C4 professor at Universität Wuppertal (Germany) in 1996. She was a research professor at the Tyndall National Institute, University College Cork (Ireland), from 2004 to 2008. Since May 2007 she has been an ICREA Research Professor based at the Catalan Institute of Nanoscience and Nanotechnology (formerly, the ICN).

She has received awards from the Royal Society of Edinburgh, the Nuffield Foundation and an Amelia Earhart Fellowship from Zonta International (USA). In 2020 she was awarded an ERC Advanced Grant to lead a five-year project (starting in January 2021) aiming at developing a disruptive technology based on phononic interconnects to reduce energy consumption of electronic circuits.

Prof. Dr Sotomayor Torres, who is a member of the Academia Europeae, is author of over 560 scientific papers, 515 of which are indexed (ORCID, WoS, Researcher ID: E-8418-2010), has an h-index of 49 and over 9500 citations. She edited six books on low dimensional structures and nanofabrication.

She leads a strong team working on phonon engineering and is actively engaged in European research. She represents the ICN2 in the Nanoelectronics AENEAS Joint Undertaking (Chamber B).

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