New Lithium- and Diamines-Intercalated Superconductors Li$_x$(C$_2$H$_8$N$_2$)$_y$TiSe$_2$ and Li$_x$(C$_6$H$_{16}$N$_2$)$_y$TiSe$_2$

TL;DR

This paper reports the synthesis of new lithium- and diamine-intercalated TiSe2 superconductors with transition temperatures around 4.2 K, demonstrating how intercalation induces superconductivity by suppressing charge density waves.

Contribution

The study introduces novel intercalation compounds of TiSe2 with lithium and diamines, showing their superconducting properties and mechanisms.

Findings

Li and diamine intercalation induces superconductivity in TiSe2.

Interlayer expansion and electron doping suppress charge density waves.

New superconductors with Tc up to 4.2 K were synthesized.

Abstract

New intercalation superconductors of Li$_x$(C$_2$H$_8$N$_2$)$_y$TiSe$_2$ and Li$_x$(C$_6$H$_{16}$N$_2$)$_y$TiSe$_2$ with $T_{\rm c}$ = 4.2 K have successfully been synthesized via the co-intercalation of lithium and ethylenediamine or hexamethylenediamine into 1T-TiSe$_2$. Moreover, it has been found that both intercalation compounds of Li$_x$TiSe$_2$ and (C$_2$H$_8$N$_2$)$_y$TiSe$_2$ also show superconductivity with $T_{\rm c}$ = 2.4 K and 2.8 K, respectively. These results indicate that both the electron doping due to the intercalation of lithium and the expansion of the interlayer spacing between TiSe2 layers due to the intercalation of diamines suppress the charge density wave in 1T-TiSe$_2$, leading to the appearance of superconductivity.