Two-stage magnetic-field-tuned superconductor-insulator transition in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$

Abstract

In the underdoped pseudogap regime of cuprate superconductors, the normal state is commonly probed by applying a magnetic field ($H$). However, the nature of the $H$-induced resistive state has been the subject of a long-term debate, and clear evidence for a zero-temperature ($T=0$) $H$-tuned superconductor-insulator transition (SIT) has proved elusive. Here we report magnetoresistance measurements in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$, providing striking evidence for quantum critical behavior of the resistivity -- the signature of a $H$-driven SIT. The transition is not direct: it is accompanied by the emergence of an intermediate state, which is a superconductor only at $T=0$. Our finding of a two-stage $H$-driven SIT goes beyond the conventional scenario in which a single quantum critical point separates the superconductor and the insulator in the presence of a perpendicular $H$. Similar two-stage $H$-driven SIT, in which both disorder and quantum phase fluctuations play an important role, may also be expected in other copper-oxide high-temperature superconductors.

23 pages, 5 figures, and Supplementary Information (11 pages, 7 figures); Article

References in corpus (5)

• Direct observation of the flux-line vortex glass phase in a type II superconductor
• Total suppression of superconductivity by high magnetic fields in YBa2 Cu3O6.6
• Evidence for Charge Glass-like Behavior in Lightly Doped La_{2-x}Sr_{x}CuO_{4} at Low Temperatures
• Superconductor-insulator quantum phase transition
• Non-Gaussian Noise in the In-Plane Transport of Lightly Doped La_{2-x}Sr_{x}CuO_4: Evidence for a Collective State of Charge Clusters

Cited by in corpus (4)

• Highly crystalline 2D superconductors
• Electronic structure of transferred graphene/h-BN van der Waals heterostructures with nonzero stacking angles by nano-ARPES
• Structural properties and magnetoresistance of La${}_{1.952}$Sr${}_{0.048}$CuO${}_4$ thin films
• Current-voltage characteristics and vortex dynamics in highly underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$