How to map a pseudogap?

TL;DR

This paper critically examines the concept of the pseudogap in cuprate superconductors, arguing that recent experimental claims about its magnetic field dependence are inconsistent and unsupported by data.

Contribution

It challenges recent experimental interpretations of the pseudogap collapse, highlighting inconsistencies and fallacious assumptions in prior work.

Findings

The pseudogap collapse is due to spin-splitting, not orbital effects.

The Zeeman relation $k_BT^*=gB_{pg}$ is questioned.

Recent experimental claims are unsupported and inconsistent.

Abstract

A pseudogap (PG) is believed to be responsible for the non Fermi-liquid normal state of cuprate superconductors. In particular, field induced PG collapse causes negative longitudinal magnetoresistance (MR), for details, see V.N. Zavaritsky, M. Springford, A.S. Alexandrov, cond-mat/0006089; cond-mat/0011192. The PG collapses because of spin-splitting of the polaron band while the orbital effects are irrelevant. Recently these conclusions, including the Zeeman relation, $k_BT^*=gB_{pg}$, which couples the PG temperature, $T^*$, and the PG closing field, $B_{pg}$, were reaffirmed by T. Shibauchi {\it et al.}, Phys. Rev. Lett. {\bf 86}, 5763 (2001). It will demonstrate that the article by T. Shibauchi {\it et al.} lacks consistency and its conclusions are based on fallacious propositions and unsupported by the authors' own experimental results.