Mechanism of metallization and superconductivity suppression in YBa_2(Cu_2.97 Zn_0.03)_3 O_6.92 revealed by 67Zn NQR

Pelc, Damjan and Požek, Miroslav and Despoja, Vito and Sunko, Denis K. (2015) Mechanism of metallization and superconductivity suppression in YBa_2(Cu_2.97 Zn_0.03)_3 O_6.92 revealed by 67Zn NQR. New Journal of Physics, 17 (8). pp. 83033-1. ISSN 1367-2630

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Abstract

We measure the NQR signal on the Zn site in nearly optimally doped YBa2Cu3O6:92, when Cu is substituted by 3% isotopically pure 67Zn. We observe that Zn creates large insulating islands, confirming two earlier conjectures, that doping provokes an orbital transition in the CuO2 plane, which is locally reversed by Zn substitution, and that the islands are antiferromagnetic. Cluster and DFT calculations show that the D4 symmetry breaking, observed directly in the NQR signal here, is due to the same partial lifting of degeneracy of the nearest-neighbor oxygen sites as in the LTT transition in La2-xBaxCuO4, similarly well-known to strongly suppress superconductivity. These results prove that in-plane oxygen 2p5 orbital configurations are principally involved in the metallicity and SC of all high-Tc cuprates, and provide a qualitative symmetry-based constraint on the SC mechanism.

Item Type: Article
Keywords: high-temperature superconductors; zinc doping; NQR; DFT
Date: 18 August 2015
Subjects: NATURAL SCIENCES > Physics
Additional Information: © 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Received 25 April 2015. Revised 3 June 2015. Accepted for publication 10 July 2015. Published 18 August 2015.
Divisions: Faculty of Science > Department of Physics
Project code: 119-1191458-0512, 202301-202353, IP-11-2013-2729
Publisher: IOP Institute of Physics
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 26 Mar 2017 17:07
Last Modified: 02 Dec 2017 17:55
URI: http://digre.pmf.unizg.hr/id/eprint/5473

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