Carlo Grazianetti

Helicity‐sensitive photocurrents provide a direct fingerprint of broken inversion symmetry and spin–orbit coupling in quantum materials. However, it is unclear whether they persist in structurally disordered systems. Here, we report the observation of the circular photocurrents in polycrystalline tellurium (Te) thin films grown via physical vapor deposition. Under zero‐bias illumination with circularly polarized light, the photocurrent exhibits the well‐defined modulation characteristic of circular photogalvanic effect (CPGE). While the traditional fitting procedure makes assumptions about the structure of the signal, we also use a Fourier‐based approach to extract the full set of periodic components in a model‐independent way. This reveals a dominant term linked to reflectivity modulation and a distinct contribution consistent with a helicity‐sensitive response. The emergence of the CPGE in a film composed of randomly oriented Te nanocrystals is attributed to its intrinsic circular dichroism. These results demonstrate that chirality‐driven photocurrents can persist in disordered systems lacking long‐range crystalline order. Spin‐ and polarization‐dependent effects are thus compatible with scalable, polycrystalline architectures, supporting their integration into chiral optoelectronic and spintronic platforms.

The topological properties of matter have reached nowadays a broad interest in the scientific and technological communities, mostly because those properties, initially exotic and hard to follow, have now demonstrated exploitability in everyday‐life applications. In this light, beyond expanding our knowledge in the condensed matter physics field as well as revisiting some definitions of solid‐state physics, the topological properties of materials might provide substantial benefits for challenges involving human society and environment. Here, we review the topological materials like topological insulators, quantum valley Hall and quantum spin Hall insulators, and topological Weyl and Dirac semimetals aiming at spotlighting the most recent advancements in fields like spintronics, electronics, photonics, thermoelectrics, and catalysis. Finally, we provide with an outlook on the recent class of topological materials like kagome, Lieb and moiré heterostructures which are expected to further expand the wealth of applications based on topological properties of matter.

Platinum ditelluride (PtTe ₂ ) is a type‐II Dirac semimetal featuring tilted cones in its electronic band structure, which leads to intriguing electronic and optical topological properties. Here, a large area growth process is presented for the synthesis of PtTe ₂ films with nanoscale thickness by sputtering deposition of a Pt precursor layer and subsequent tellurization at 450 °C. Although the Pt deposition step does not pose stringent limitation on the substrate choice, it is demonstrated that the heating rate during the tellurization step can induce a significant thermal‐induced strain when the process is extended from silicon dielectric transparent silica substrates, leading to macroscopic wrinkling of the PtTe ₂ film. Thus, a slower tellurization process is optimized, successfully resulting in stress‐free growth even on dielectric substrates. Additionally, the same new process repeated on silicon substrates shows a threefold enhanced minimum grain size compared to the original process. These accomplishments, combined with the scalability of the growth technique and the deterministic material patterning achieved by optical lithography, are crucial for a facile integration of PtTe ₂ in any kind of device.

Ultra-thin Te films exhibit enhanced resistive switching behavior when directly grown on Au(111) substrate with an engineered superficial herringbone reconstruction.

All-optical neuromorphic devices based on adaptive two-dimensional (2D) materials have the potential for mimicking the complex processing and memory capabilities of biological synapses. Recent research demonstrated synaptic plasticity and visual memory in WS₂ monolayer-based 2D memitters (i.e., an emitter with memory). However, improving their optical performances is crucial for extending their scalability. Since the neuromorphic functionalities of 2D memitters relies on O₂ and H₂O desorption/absorption on WS₂, a careful balance between photoluminescence intensity and surface preservation is critical. Here, we investigate the enhancement of time-dependent photoluminescence response, achieved through coupling WS₂ flakes with plasmonic nanoparticles obtained by liquid phase infiltration of gold in self-assembled block copolymer micelles. The localized surface plasmon resonance of gold nanoparticles amplifies the electric field and improves light-matter interactions. This method enhances the 2D memitter optical properties while preserving its adaptive photoluminescence response, thus enabling neuromorphic behavior under optical stimuli.

Two‐dimensional (2D) materials are promising for resistive switching in neuromorphic and in‐memory computing, as their atomic thickness substantially improve the energetic budget of the device and circuits. However, many 2D resistive switching materials struggle with complex growth methods or limited scalability. 2D tellurium exhibits striking characteristics such as simplicity in chemistry, structure, and synthesis making it suitable for various applications. This study reports the first memristor design based on nanoscaled tellurium synthesized by vapor transport deposition (VTD) at a temperature as low as 100 °C fully compatible with back‐end‐of‐line processing. The resistive switching behavior of tellurium nanosheets is studied by conductive atomic force microscopy, providing valuable insights into its memristive functionality, supported by microscale device measurements. Selecting gold as the substrate material enhances the memristive behavior of nanoscaled tellurium in terms of reduced values of set voltage and energy consumption. In addition, formation of conductive paths leading to resistive switching behavior on the gold substrate is driven by gold‐tellurium interface reconfiguration during the VTD process as revealed by energy electron loss spectroscopy analysis. These findings reveal the potential of nanoscaled tellurium as a versatile and scalable material for neuromorphic computing and underscore the influential role of gold electrodes in enhancing its memristive performance.