Malinowski A, Bezusyy VL, Nowicki P. Pseudogap in underdoped cuprate seen in longitudinal magnetoresistance.
JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022;
34:415602. [PMID:
35878602 DOI:
10.1088/1361-648x/ac8405]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
We report the results of in-plane magnetotransport study of slightly underdoped cuprate La1.85Sr0.15CuO4(LSCO15) with Ni impurity. Increasing Ni contentycauses a sharp drop in longitudinal magnetoresistance (LMR) in LSCO15 to broaden and move towards higher temperatures. TemperatureTmLMR(y)of this local maximum in LMR coincides with temperatureTdev(y), below which ideal resistivity from the parallel-resistor model deviates from itsT2-dependence. A direct comparison with the hole doping evolution of pseudogap (PG) in La2-xSrxCuO4(LSCO), possible through the mobile-carrier concentration extracted from the thermopower measurements, allows to equate both characteristic temperaturesTmLMR≅Tdevwith PG opening temperatureT∗. The rate of PG closing by magnetic field parallel to the CuO2plane, in measurements up to 9 T, is consistent with spin-paramagnetic effect in this configuration and yields PG closing fieldBpcclose to the second critical fieldBc2predicted for superconducting gap with the help of Werthamer-Helfand-Hohenberg theory. The field anisotropy ofBpcsuggests that orbital degrees of freedom also play a role in PG formation.
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