Figure 1: Resistivity and Hall behavior of LiTi₂O₄ thin films.

(a)ρ_xx(T) of two samples. They have similar resistivity (∼500 μΩ cm) at room temperature, and the same T_c of 11 K, but different residual resistivity ratios (RRR): RRR∼6.25 for Sample L1 (black curve) and ∼3 for the Sample L2 (red curve). The resistivity curve from 40 to 120 K can be fit by ρ=ρ₀+AT² (grey lines). (b) The Hall resistivity is proportional to the magnetic field at different temperatures, and all the ρ_xy(B) curves overlap in the normal state (only data on Sample L1 are shown here), suggesting a simple one band-structure and a temperature-independent Hall coefficient. Note that at very low temperatures, the magnetic field is not sufficient to suppress the superconductivity (B⊥ab plane). (c) Hall coefficient versus temperature for both samples (L1: solid symbols. L2: open symbols). Though the two samples show different RRR, their Hall coefficient values are very close to each other. Assuming R_H =1/(ne), we find a hole concentration of ∼3 × 10²² cm⁻³, which is almost constant over the entire measured temperature range.