Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4

The long-standing quest to determine the superconducting order of Sr2RuO4 (SRO) has received renewed attention after recent nuclear magnetic resonance (NMR) Knight shift experiments have cast doubt on the possibility of spin-triplet pairing in the superconducting state. As a putative solution, encom...

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Main Authors: Wagner, G, Røising, HS, Flicker, F, Simon, SH
Format: Journal article
Language:English
Published: American Physical Society 2021
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author Wagner, G
Røising, HS
Flicker, F
Simon, SH
author_facet Wagner, G
Røising, HS
Flicker, F
Simon, SH
author_sort Wagner, G
collection OXFORD
description The long-standing quest to determine the superconducting order of Sr2RuO4 (SRO) has received renewed attention after recent nuclear magnetic resonance (NMR) Knight shift experiments have cast doubt on the possibility of spin-triplet pairing in the superconducting state. As a putative solution, encompassing a body of experiments conducted over the years, a (d + ig)-wave order parameter caused by an accidental near-degeneracy has been suggested [S. A. Kivelson et al., npj Quantum Materials 5, 43 (2020)]. Here we develop a general Ginzburg–Landau theory for multiband superconductors. We apply the theory to SRO and predict the relative size of the order parameter components. The heat capacity jump expected at the onset of the second order parameter component is found to be above the current threshold deduced by the experimental absence of a second jump. Our results tightly restrict theories of d + ig order, and other candidates caused by a near-degeneracy, in SRO. We discuss possible solutions to the problem.
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spelling oxford-uuid:a0fdf53a-ce0e-4302-8401-a00cbbb7f82a2022-03-27T02:09:48ZMicroscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a0fdf53a-ce0e-4302-8401-a00cbbb7f82aEnglishSymplectic ElementsAmerican Physical Society2021Wagner, GRøising, HSFlicker, FSimon, SHThe long-standing quest to determine the superconducting order of Sr2RuO4 (SRO) has received renewed attention after recent nuclear magnetic resonance (NMR) Knight shift experiments have cast doubt on the possibility of spin-triplet pairing in the superconducting state. As a putative solution, encompassing a body of experiments conducted over the years, a (d + ig)-wave order parameter caused by an accidental near-degeneracy has been suggested [S. A. Kivelson et al., npj Quantum Materials 5, 43 (2020)]. Here we develop a general Ginzburg–Landau theory for multiband superconductors. We apply the theory to SRO and predict the relative size of the order parameter components. The heat capacity jump expected at the onset of the second order parameter component is found to be above the current threshold deduced by the experimental absence of a second jump. Our results tightly restrict theories of d + ig order, and other candidates caused by a near-degeneracy, in SRO. We discuss possible solutions to the problem.
spellingShingle Wagner, G
Røising, HS
Flicker, F
Simon, SH
Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title_full Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title_fullStr Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title_full_unstemmed Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title_short Microscopic Ginzburg–Landau theory and singlet ordering in Sr2RuO4
title_sort microscopic ginzburg landau theory and singlet ordering in sr2ruo4
work_keys_str_mv AT wagnerg microscopicginzburglandautheoryandsingletorderinginsr2ruo4
AT røisinghs microscopicginzburglandautheoryandsingletorderinginsr2ruo4
AT flickerf microscopicginzburglandautheoryandsingletorderinginsr2ruo4
AT simonsh microscopicginzburglandautheoryandsingletorderinginsr2ruo4