Electrointercalation of Cu into 2H-TaS2: in situ monitoring of reaction and Cu mobility

We investigated the¹⁸¹Ta nuclear quadrupole interaction (NQI) in crystals of Cu_x TaS₂ by time differential perturbed angular correlation (TDPAC) both in situ during galvanostatic intercalation at 300 K and subsequently between 11 K and 813 K. During electrointercalation the spectra show broad frequency distributions due to slowly diffusing Cu⁺ in the van der Waals gap. The line narrowing upon heating to 813 K can be described by a simple two site jump model. Within this model we derive an activation enthalpy for Cu⁺ jumps of about 290 meV.