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Title: Vortex phase diagram and the normal state of cuprates with charge and spin orders
The phase diagram of underdoped cuprates in a magnetic field ( H ) is key to understanding the anomalous normal state of these high-temperature superconductors. However, the upper critical field ( H c2 ), the extent of superconducting (SC) phase with vortices, and the role of charge orders at high H remain controversial. Here we study stripe-ordered La-214, i.e., cuprates in which charge orders are most pronounced and zero-field SC transition temperatures T c 0 are lowest. This enables us to explore the vortex phases in a previously inaccessible energy scale window. By combining linear and nonlinear transport techniques sensitive to vortex matter, we determine the T − H phase diagram, directly detect H c2 , and reveal novel properties of the high-field ground state. Our results demonstrate that quantum fluctuations and disorder play a key role as T → 0 , while the high-field ground state is likely a metal, not an insulator, due to the presence of stripes.
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Science Advances
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National Science Foundation
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