Title: Classical topological order in the kinetics of artificial spin ice

Abstract

Systems of interacting nanomagnets known as “artificial spin ice” have allowed the design, realization and study of geometrically frustrated exotic collective states that are absent in natural magnets. We have experimentally measured , the thermally induced moment fluctuations in the Shakti geometry of artificial spin ice. We show that its disordered moment configuration is a topological phase described by an emergent dimer-cover model with excitations that can be characterized as topologically charged defects. Examination of the low-energy dynamics of the system confirms that these effective topological charges have long lifetimes associated with their topological protection, i.e., they can be created and annihilated only as charge pairs with opposite sign and are kinetically constrained. This manifestation of classical topological order demonstrates that geometrical design in nanomagnetic systems can lead to emergent, topologically protected kinetics that can limit pathways to equilibration and ergodicity.

Authors:

Lao, Yuyang ^[1]; Caravelli, Francesco  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-7964-3030"
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Sheikh, Mohammed ^[3]; Sklenar, Joseph ^[1]; Gardeazabal, Daniel  ^[1];

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Watts, Justin D. ^[4]; Albrecht, Alan M. ^[5]; Scholl, Andreas ^[6]; Dahmen, Karin ^[3]; Nisoli, Cristiano  ^[3];

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• Search DOE PAGES for ORCID "0000-0003-0053-1023"
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Schiffer, Peter ^[1]

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+ Show Author Affiliations

1. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physics, and Frederick Seitz Materials Research Lab.
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division, Inst. for Materials Science, and Center for Nonlinear Studies
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
4. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science; Univ. of Minnesota, Minneapolis, MN (United States). School of Physics and Astronomy
5. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science
6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

2018-04-02

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of Illinois at Urbana-Champaign, IL (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division

OSTI Identifier:

1479948

Alternate Identifier(s):

OSTI ID: 1485098; OSTI ID: 1594859

Report Number(s):

LA-UR-17-29552
Journal ID: ISSN 1745-2473

Grant/Contract Number:  

AC52-06NA25396; AC02-05CH11231; SC0010778

Resource Type:

Accepted Manuscript

Journal Name:

Nature Physics

Additional Journal Information:

Journal Volume: 14; Journal Issue: 7; Journal ID: ISSN 1745-2473

Publisher:

Nature Publishing Group (NPG)

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS