Nexus between quantum criticality and the chemical potential pinning in high-$T_c$ cuprates

TL;DR

This paper explores the relationship between quantum criticality and chemical potential pinning in high-temperature cuprate superconductors, revealing a topological origin of the phenomenon linked to charge gauge symmetry and ground state degeneracy.

Contribution

It uncovers a topological quantum criticality mechanism explaining chemical potential pinning in strongly correlated electrons, distinct from traditional symmetry-breaking theories.

Findings

Pinning of chemical potential is linked to topological charge divergence.

Charge compressibility diverges at zero temperature, indicating quantum criticality.

Topological charges govern the quantum critical behavior in cuprates.

Abstract

For strongly correlated electrons the relation between total number of charge carriers $n_e$ and the chemical potential $\mu$ reveals for large Coulomb energy the apparently paradoxical pinning of $\mu$ within the Mott gap, as observed in high-$T_c$ cuprates. By unravelling consequences of the non-trivial topology of the charge gauge U(1) group and the associated ground state degeneracy we found a close kinship between the pinning of $\mu$ and the zero-temperature divergence of the charge compressibility $\kappa\sim\partial n_e/\partial\mu$, which marks a novel quantum criticality governed by topological charges rather than Landau principle of the symmetry breaking.