Berry curvature dipole-induced non-linear Hall effects in oxide superlattices

Abstract

The observation of non-linear Hall effects in time-reversal invariant systems has established the intriguing role of band topology beyond Berry curvature in determining transport phenomena. Many of these non-linear responses owe their origin to the Berry curvature dipole (BCD), which, like the Berry curvature (monopole), is also an electronic band structure effect, but is routinely strongly constrained by crystalline symmetries. Here, we propose non-centrosymmetric transition metal oxide superlattices as promising platforms for realizing and tuning BCD-induced non-linear Hall effects. Specifically, we investigate superlattices of the form (Ba(Os,Ir)O₃)_n/(BaTiO₃)₄ (n = 1, 2), comprising metallic perovskite layers (BaOsO₃ or BaIrO₃) sandwiched between insulating ferroelectric BaTiO₃ (BTO). The ferroelectric distortion in BTO breaks the inversion symmetry of the superlattice, giving rise to a finite BCD with two symmetry-allowed components of equal magnitude and opposite sign. Our first-principles calculations demonstrate that the magnitude of the BCD – and consequently the nonlinear Hall response – can be effectively tuned by varying the number of metallic layers or the choice of the B-site cation in these ABO₃ perovskites. Since Rashba splitting and ferroelectric distortion in these systems are readily controllable via an external electric field or strain, the non-linear Hall response in these materials can be directly engineered. Our findings establish non-centrosymmetric oxide perovskite superlattices as a versatile platform for exploring and manipulating BCD-driven non-linear transport phenomena.