Doping dependence of the upper critical field in La_{2-x}Sr_xCuO_4 from specific heat

TL;DR

This study investigates how the upper critical magnetic field in La_{2-x}Sr_xCuO_4 varies with doping, revealing a doping-dependent behavior similar to the critical temperature, and suggests an underlying energy scale influencing superconductivity.

Contribution

It provides a comprehensive mapping of the upper critical field across the doping range in LSCO using specific heat measurements, highlighting a doping dependence similar to T_c.

Findings

H_{c2} varies with doping similarly to T_c

Proposes an effective energy scale for superconductivity in underdoped LSCO

Maps H_{c2} across the entire superconducting dome

Abstract

The low-temperature specific heat of La_{2-x}Sr_xCuO_4 (LSCO) single crystals in magnetic field H up to 12 T has been examined over a wide range of doping (0.063=< p =<0.238). From this we have mapped the upper critical field H_{c2} of LSCO across the entire superconducting diagram. It is found that the H_{c2} shows a doping dependence similar to that of the critical temperature T_c. We have discussed the implications of the result and proposed that there may be an effective superconducting energy scale responsible for the H_{c2} behavior in the underdoped region.