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T. Antonelli

Publications and source records attributed to T. Antonelli.

2 recordsLinked to original sources
arXiv2025

Finite Length Effects and Coulomb Interaction in Ge Quantum Well-Based Josephson Junctions Probed with Microwave Spectroscopy

Proximitized Ge quantum wells have emerged as a novel platform for studying Andreev bound states (ABSs), due to their expected strong spin-orbit interaction and high mobility. Here, we used microwave spectroscopy techniques to investigate ABSs in Josephson junctions (JJs) realized in proximitized Ge quantum wells. Spectroscopic signatures observed in a 350 nm junction indicated the presence of multiple ABSs, and were reproduced with a model including finite-length effects. The ABS spectra measured for a $1.2~\mu$m junction were explained by a model including three ABSs in two conduction channels and finite Coulomb interaction. Our work highlights the importance of interactions in JJs and serves as a basis for understanding and manipulating ABSs in Ge-based hybrid devices.

cond-mat.mes-hall↗
arXiv2022

Orbital-selective Band Hybridisation at the Charge Density Wave Transition in Monolayer TiTe$_2$

An anomalous $(2\times2)$ charge density wave (CDW) phase emerges in monolayer 1T-TiTe$_2$ which is absent for the bulk compound, and whose origin is still poorly understood. Here, we investigate the electronic band structure evolution across the CDW transition using temperature-dependent angle-resolved photoemission spectroscopy. Our study reveals an orbital-selective band hybridisation between the backfolded conduction and valence bands occurring at the CDW phase transition, which in turn leads to a significant electronic energy gain, underpinning the CDW transition. For the bulk compound, we show how this energy gain is almost completely suppressed due to the three-dimensionality of the electronic band structure, including via a $k_z$-dependent band inversion which switches the orbital character of the valence states. Our study thus sheds new light on how control of the electronic dimensionalilty can be used to trigger the emergence of new collective states in 2D materials.

cond-mat.str-el↗