Giant spontaneous Hall effect in a nonmagnetic Weyl–Kondo semimetal

Abstract

Nontrivial topology in condensed-matter systems enriches quantum states of matter to go beyond either the classification into metals and insulators in terms of conventional band theory or that of symmetry-broken phases by Landau’s order parameter framework. So far, focus has been on weakly interacting systems, and little is known about the limit of strong electron correlations. Heavy fermion systems are a highly versatile platform to explore this regime. Here we report the discovery of a giant spontaneous Hall effect in the Kondo semimetal Ce3Bi4Pd3 that is noncentrosymmetric but preserves time-reversal symmetry. We attribute this finding to Weyl nodes—singularities of the Berry curvature—that emerge in the immediate vicinity of the Fermi level due to the Kondo interaction. We stress that this phenomenon is distinct from the previously detected anomalous Hall effect in materials with broken time-reversal symmetry; instead, it manifests an extreme topological response that requires a beyond-perturbation-theory description of the previously proposed nonlinear Hall effect. The large magnitude of the effect in even tiny electric and zero magnetic fields as well as its robust bulk nature may aid the exploitation in topological quantum devices.

Terahertz detection based on nonlinear Hall effect without magnetic field

“…B is allowed by symmetry in noncentrosymmetric crystals and surfaces having certain point groups (see below). For example, in materials with a polar axis, large B has been found due to the presence of tilted Dirac or Weyl points in the band structure (6,(27)(28)(29)(30)(31)(32)(33)(34)(35). When B is nonzero and in the presence of an applied electric field, the imbalance in the probability of occupation f (k) = f (−k) leads to a net Berry curvature, which then induces a second-order anomalous current in the transverse direction.…”

Quantum theory of the nonlinear Hall effect

“…The Berry curvature dipole describes the dipole moment of the Berry curvature in momentum space 1 . In addition, the nonlinear Hall effect is a quantum transport phenomenon near the dc limit because of the extremely low frequency (~10 to 1000 Hz) of the input currents in experiments 7,8,[34][35][36][37][38][39][40][41] . The importance of the quantum description of dc quantum transports has been well acknowledged 42 .…”

From Trivial Kondo Insulator Ce3Pt3Bi4 to Topolog

“…In particular, the proposal of a truly heavy-fermion WKS [5] has stimulated intensive theoretical and experimental studies [7][8][9]. Experimentally, the realization of a TKI-WKS phase transition from Ce 3 Pt 3 Bi 4 to Ce 3 Pd 3 Bi 4 has recently been hotly discussed [9][10][11]. In this Letter, using state-of-art first-principles method based on density functional theory (DFT) and its combination with dynamical mean-field theory (DMFT) [12][13][14], we show that the Ce 3 Pt 3 Bi 4 is a topologically trivial Kondo insulator; while Ce 3 Pd 3 Bi 4 is a topological nodal-line Kondo semimetal, which is protected by the non-symmorphic symmetry of the crystal.…”