Title: Hyperfine and quadrupole interactions for Dy isotopes in DyPc₂ molecules

Abstract

Nuclear spin levels play a vital role in understanding magnetization dynamics and implementation and control of quantum bits in lanthanide-based single-molecule magnets. We investigate the hyperfine and nuclear quadrupole interactions for ¹⁶¹Dy and ¹⁶³Dy nuclei in anionic DyPc₂ (Pc=phthalocyanine) single-molecule magnets, using multiconfigurational ab initio methods (beyond density-functional theory) including spin–orbit interaction. The two isotopes of Dy are chosen because the others have zero nuclear spin. Both isotopes have the nuclear spin I=5/2, although the magnitude and sign of the nuclear magnetic moment differ from each other. The large energy gap between the electronic ground and first-excited Kramers doublets, allows us to map the microscopic hyperfine and quadrupole interaction Hamiltonian onto an effective Hamiltonian with an electronic pseudo-spin that corresponds to the ground Kramers doublet. Our ab initio calculations illustrate that the coupling between the nuclear spin and electronic orbital angular momentum contributes the most to the hyperfine interaction and that both the hyperfine and nuclear quadrupole interactions for ¹⁶¹Dy and ¹⁶³Dy nuclei are much smaller than those for the ¹⁵⁹Tb nucleus in TbPc₂ single-molecule magnets. The calculated separations of the electronic-nuclear levels are comparable to experimental data reported for ¹⁶³DyPc₂. We demonstrate that hyperfine interaction for the Dy Kramersmore » ion leads to tunnel splitting (or quantum tunneling of magnetization) at zero field. This effect does not occur for TbPc₂ single-molecule magnets. The magnetic field values of the avoided level crossings for ¹⁶¹DyPc₂ and ¹⁶³DyPc₂ are found to be noticeably different, which can be observed from the experiment.« less

Authors:

Wysocki, Aleksander L.  ^[1];

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Park, Kyungwha ^[1]

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+ Show Author Affiliations

1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

Publication Date:

Thu Apr 09 00:00:00 EDT 2020

Research Org.:

Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division

Contributing Org.:

San Diego Supercomputer Center (SDSC)

OSTI Identifier:

1631161

Grant/Contract Number:  

SC0018326; DMR060009N

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physics. Condensed Matter

Additional Journal Information:

Journal Volume: 32; Journal Issue: 27; Journal ID: ISSN 0953-8984

Publisher:

IOP Publishing

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; lanthanide single-molecule magnets; hyper ne coupling; nuclear quadrupole interaction; spin-orbit interaction; ab-initio calculations