Subarea law of entanglement in nodal fermionic systems

Abstract

We investigate the subarea law scaling properties of the block entropy in bipartite fermionic systems which do not have a finite Fermi surface. It is found that in gapped regimes the leading subarea term is a negative constant, whereas in critical regimes with point nodes the leading subarea law is a logarithmic additive term. At the phase boundary that separates the critical and non-critical regimes, the subarea scaling shows power-law behavior.