μSR study of time-reversal symmetry constraints and bulk superfluid response in Li_0.95FeAs

We report zero-field (ZF) and transverse-field (TF) muon-spin rotation/relaxation (μSR) measurements on superconducting Li_0.95FeAs (T_c ≃ 16.0 K) grown by a high-pressure self-flux method. The ZF-μSR data show no detectable change of the electronic relaxation rate on cooling through Tc, providing no evidence for time-reversal-symmetry breaking in the superconducting state. TF-μSR measurements reveal a well-developed vortex response with strong flux pinning and a negligible nonsuperconducting contribution, confirming that superconductivity is a bulk property of the sample. From the second moment of the internal field distribution we determine a low-temperature in-plane magnetic penetration depth λ_ab = 245(15) nm. The temperature dependence of the normalized superfluid density is well described by an effective two-gap model with Δ₁ = 2.0(2) meV and Δ₂ = 0.7(2) meV. A quantitative comparison with band weights derived from angle-resolved photoemission spectroscopy shows that the μSR response is dominated by the Fermi-surface sheets carrying the intermediate and small superconducting gaps, whereas the band hosting the largest gap contributes only about 3% to the total superfluid density and is therefore not resolved in the present analysis. Taken together, these results provide an independent bulk confirmation of nodeless multigap superconductivity in Li_0.95FeAs without detectable time-reversal-symmetry breaking and show how μSR reconciles the gap scales reported by bulk- and surface-sensitiveprobes in this multiband system.