Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide
Year: 2025
Type: article
Abstract: Transition-metal dichalcogenides (TMDs) offer an extremely rich material platform in the exploration of unconventional superconductivity. The unconventional aspects include exotic coupling mechanisms such as the Ising pairing, a complex interplay with other electronic orders such as charge-density waves (CDWs), symmetry-breaking and topological effects, and non-trivial gap structures such as multi-gap and possible nodal phases. Among TMDs, titanium diselenide (1 T -TiSe 2 ) is one of the most studied and debated cases. Hints to an anomalous structure of its superconducting order parameter have emerged over the years, possibly linked to its texturing in real and reciprocal space due to the presence of a 2×2×2 CDW phase, or to a pressure-driven multi-band Fermi surface. However, direct evidence for an unconventional structure of the superconducting gap in this material is still lacking. In this work, the combination of the temperature dependence of the upper critical field with point-contact Andreev reflection and scanning tunneling spectroscopy measurements all consistently indicate the existence of two distinct superconducting gaps in the recently-discovered H-intercalated TiSe 2 superconductor. These results provide unambiguous evidence for a non-trivial superconducting phase in TiSe 2 and stimulate further research aimed at clarifying its connection with the orbital character and its interplay with the underlying CDW order.
Source: Materials Today Physics
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,160
Funders: Slovenská Akadémia Vied, European Commission, European Cooperation in Science and Technology, Ministero dell’Istruzione, dell’Università e della Ricerca, Agentúra na Podporu Výskumu a Vývoja, Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, Ministero dell'Università e della Ricerca, NextGenerationEU
Awards: G1206388457, G15967578, G1854293338, Necentrosymetrické supravodiče, G231133531, G2728702310, G2888052283, G3764870964, G423719072, G4370874191, Tuning and understanding Quantum phases in 2D materials - Quantum2D, G490430286, G5141260536, G617794351, G6293815811, G72140814, Nízkorozmerné supravodivé aparáty, G8088548421, G8166719919, G8244342837, G972786147
OpenAlex ID: W4415020504