Room-temperature nonlinear Hall effect and enhanced voltage responsivity in symmetry-engineered La0.7Sr0.3MnO3-δ-based tricolor superlattices.

The nonlinear Hall effect (NLHE) offers a promising route to zero-bias rectification by exploiting the quadratic current dependence of the second harmonic Hall voltage at zero magnetic field. Here, the occurrence of NLHE in (001)MgO/La0.7Sr0.3MnO3-δ(LSMO) has been demonstrated only within a narrow temperature window of 200-250 K; however, interface engineering in MgO(001)/LSMO/SrTiO3/LaAlO3 tricolor superlattices, achieved through controlled thickness modulation of the SrTiO3 and LaAlO3 spacer layers, extends the operating regime to room temperature, highlighting its potential for applications. The NLHE observed in these superlattices exhibits a pronounced temperature dependence, allowing an analysis of the scaling relation between nonlinear Hall generation efficiency and longitudinal conductivity. The scaling behavior is consistent with Gaussian skew scattering as a prominent extrinsic contribution to the NLHE. The magnitudes and signs of the effective scaling coefficients further suggest a temperature-dependent competition and redistribution among interfacial-disorder, mixed interfacial-disorder-phonon, and phonon-mediated scattering mechanisms, although their individual microscopic contributions cannot be quantitatively separated. The optimized superlattice exhibits a voltage responsivity of 94 V W-1 near room temperature, underscoring the technological promise of nonlinear Hall rectification. Collectively, these results establish LSMO-based oxide superlattices as a versatile platform for symmetry-engineered nonlinear transport and high-efficiency zero-bias rectification.