The work was carried out mainly at the CUNY Advanced Science Research Center (New York, USA), and Politecnico di Milano (Milan, Italy). The activity ranged from the optimization of the tam-SPL patterning technique, to the demonstration of the building blocks of magnonic devices, to the realization of optically-inspired spin-wave platforms for analog computing. These results, reported below, set a strong basis for the realization of computing devices using spin-waves, and demonstrated the versatility and potential of thermal nanolithography for the realization of innovative nanodevice architectures.
Realization of reconfigurable spin-wave nanocircuits.
The realization of a nanoscale spin-wave circuitry for guiding and manipulating the interaction of magnons, is still an open challenge. In this work (Figure 2), we demonstrated the fundamental building blocks of spin-waves circuitry, i.e. magnonic nanowaveguides and a spin-wave circuit allowing for the tunable superposition of signals propagating in two converging waveguides. This work demonstrates that engineered spin-textures (Figure 1) represent a powerful tool for realizing such a circuitry, marking a fundamental step towards the development of nanomagnonic computing devices.
The results have been published in the papers E. Albisetti et al, Communications Physics, 1, 56 (2018), E. Albisetti et al, AIP Advances, 7(5), 55601 (2017), E. Albisetti et al, Applied Physics Letters 113, 162401 (2018).
Realization of an optically-inspired nanomagnonic platform for analog computing.
Optically-inspired wave-based processing is envisioned to outperform digital architectures in specific tasks, such as image processing and speech recognition. In this work (Figure 3), an optically-inspired platform using spin waves is realized for the first time, demonstrating the wavefront engineering and interference of spin waves with nanoscale wavelength. In particular, magnonic nanoantennas based on spin textures are used for launching spatially shaped wavefronts, diffraction-limited spin-wave beams, and generating robust multi-beam interference patterns, which spatially extend for several times the spin-wave wavelength. The unique combination of these features gives rise to a versatile playground for studying the physics of nonreciprocal spin-wave propagation, and represents a fundamental step towards optically-inspired spin-wave processing. The results of this work have been accepted for publication in Advanced Materials (preprint arXiv:1902.09420).
Realization of field-effect transistors on 2D semiconductors via thermal nanolithography
One of the critical aspects in the fabrication of high-performance field-effect transistors on 2D semiconductors is the realization of high-quality metal/semiconductor contacts. The low quality of such contacts is in fact often the limiting factor in the performance of the FETs. In this work (Figure 4), a novel methodology based on thermally assisted scanning probe lithography is presented for nanofabricating low resistivity contacts on 2D materials. Compared to Electron Beam Lithography, this approach offers advantages in terms of device performance and capabilities, and could lead to low-cost, one-step industrial metal nanomanufacturing for the fabrication of integrated nanoelectronic computing platforms.
The results of this work have been published in the paper: X. Zheng, A. Calò, E. Albisetti et al, Nature Electronics 2, 17–25 (2019).
