Emergent nodal non-Fermi liquid behavior from a Berry dipole

The study of topological phases has been an intriguing area of research in condensed matter physics for over a decade. In this work, we investigate the effects of long-range Coulomb interaction at the topological quantum critical point (TQCP) between a Hopf insulator and a trivial insulator. At the TQCP, the band-crossing point realizes a Berry dipole [1], and fermionic states in its vicinity strongly couple with the Coulomb field. Using perturbative renormalization group methods, we identify that the Coulomb interaction drives the system into a new type of quasiparticleless critical state [2]. The nodal non-Fermi liquid, thus obtained, controls finite temperature behaviors over a wide region of the phase diagram. We derive the associated scaling behaviors of various observables, and explore possible experimental realizations.

[1] A. Nelson, et al., Phys. Rev. B 106, 075124 (2022)

[2] K. Ladovrechis and S. Sur, (to appear)