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Title: Anomalous quantum criticality in the electron-doped cuprates

In the physics of condensed matter, quantum critical phenomena and unconventional superconductivity are two major themes. In electron-doped cuprates, the low critical field (HC2) allows one to study the putative quantum critical point (QCP) at low temperature and to understand its connection to the long-standing problem of the origin of the high-TCsuperconductivity. Here we present measurements of the low-temperature normal-state thermopower (S) of the electron-doped cuprate superconductor La2−xCexCuO4(LCCO) fromx= 0.11–0.19. We observe quantum criticalS/Tversusln(1/T)behavior over an unexpectedly wide doping rangex= 0.15–0.17 above the QCP (x= 0.14), with a slope that scales monotonically with the superconducting transition temperature (TCwith H = 0). The presence of quantum criticality over a wide doping range provides a window on the criticality. The thermopower behavior also suggests that the critical fluctuations are linked withTC. Above the superconductivity dome, atx= 0.19, a conventional Fermi-liquidSTbehavior is found forT40 K.

 
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Award ID(s):
1708334
NSF-PAR ID:
10087945
Author(s) / Creator(s):
; ;
Publisher / Repository:
Proceedings of the National Academy of Sciences
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
116
Issue:
13
ISSN:
0027-8424
Page Range / eLocation ID:
p. 5991-5994
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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