In the physics of condensed matter, quantum critical phenomena and unconventional superconductivity are two major themes. In electrondoped cuprates, the low critical field (H_{C2}) allows one to study the putative quantum critical point (QCP) at low temperature and to understand its connection to the longstanding problem of the origin of the high
We report results of largescale groundstate density matrix renormalization group (DMRG) calculations on t
 Award ID(s):
 2110041
 Publication Date:
 NSFPAR ID:
 10307360
 Journal Name:
 Proceedings of the National Academy of Sciences
 Volume:
 118
 Issue:
 44
 Page Range or eLocationID:
 Article No. e2109978118
 ISSN:
 00278424
 Publisher:
 Proceedings of the National Academy of Sciences
 Sponsoring Org:
 National Science Foundation
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T_{C} superconductivity. Here we present measurements of the lowtemperature normalstate thermopower (S ) of the electrondoped cuprate superconductor La_{2−x}Ce_{x}CuO_{4}(LCCO) fromx = 0.11–0.19. We observe quantum critical$\mathit{S}/\mathit{T}$ versus$\mathbf{l}\mathbf{n}\left(\mathbf{1}/\mathit{T}\right)$ 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 (T_{C} with 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 withT_{C} . Above the superconductivity dome, atx = 0.19, a conventional Fermiliquid$\mathit{S}\propto \mathit{T}$ behavior is found for$\mathit{T}\le $ 40 K. 
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