Magnetic field as a probe of gap energy scales in YBCO

TL;DR

This paper proposes that magnetic field measurements can reveal a new energy scale in YBCO superconductors, distinct from the d-wave gap, observable through thermodynamic properties like specific heat.

Contribution

It introduces the idea that magnetic fields can detect a unique energy scale associated with chains in YBCO, separate from the known superconducting gap.

Findings

Discontinuity in density of states as a function of magnetic field

Identification of a new energy scale in YBCO

Potential experimental observables in specific heat

Abstract

Among high T_c materials, the YBCO (YBa_2Cu_3O_{7-x}) compounds are special since they have superconducting chains as well as planes. We show that a discontinuity in the density of states as a function of magnetic field may appear at a new energy scale, characteristic of the chain and distinct from that set by the d wave gap. This is observable in experimental studies of the thermodynamical properties of these systems, such as the specific heat.