Orateur
Description
Lithium intercalation is a powerful approach to realizing emergent quantum phenomena in a variety of material systems. Here we report our recent studies of lithium intercalated superconductors by utilizing a solid lithium-ion conductor. We transfer exfoliated materials such as TiSe2 [1,2], Bi2Sr2CaCu2O8+x (Bi-2212) [3], and FeSe [4] on this conductor. The exfoliated flakes can be intercalated with lithium by applying a positive gate voltage to the backside of the solid ion conductor. Such a simple method allows us to explore intriguing superconducting properties.
In TiSe2, we realize a superconducting dome by lithium doping. Anomalous metal phase emerges around the optimally doped regime. Tunneling spectroscopy reveals a symmetric gap even in this anomalous metal phase. Furthermore, both resistance measurements and tunneling spectroscopy show oscillations with a perpendicular magnetic field, suggesting a spontaneously formed superconducting network. We confirm the similar resistance oscillations in Bi-2212 in the underdoped regime. This finding indicates that superconducting networks emerge in different material systems.
In FeSe, we observe that lithium intercalation brings together both high-temperature superconductivity and ferromagnetism. The coexistence of two usually antagonistic phenomena suggests possible formation of spin triplet Cooper pairing.
References:
[1] M. Liao, et al., Nat. Commun. 12, 5342 (2021).
[2] J.-Y. Ji, et al., Nano Lett. 25, 10641 (2025).
[3] M. Liao, et al., Nat. Commun. 13, 1316 (2022).
[4] Y. Hu, et al., Nat. Commun. 16, 7305 (2025).