Quantum tunneling of the zeroth Laudau level in YbMnBi2

The advance of condensed matter physics has been promoted by the discoveries of novel quantum materials. The recently discovered topological semimetals, including topological Dirac, Weyl, and Nodal-line semimetals, have attracted enormous attentions. This talk will focus on our recent discovery of the quantum tunneling of the relativistic fermions in the interlayer transport of YbMnBi2. Unlike normal electrons, under magnetic fields, relativistic fermions acquire Berry phase of π in cyclotron motion, leading to a zeroth Landau level (LL) at the band crossing point. In YbMnBi2, the 0th LL Weyl fermions exhibit quantum tunneling between the neighboring Bi square-net layers, causing surprising interlayer magnetotransport properties. Our results revealed the first example of the quantum tunneling directly from the zeroth LL’s Weyl fermions, shedding light on the unusual role of zeroth LL mode in transport.