Emergence by design in artificial spin ice

Intriguing phenomena generally emerge from the collective behavior of numerous simple interacting degrees of freedom. Indeed, physicists typically first discover new systems and then proceed to describe them via higher level models that often deliberately neglect the detail of the building blocks. Instead, they concentrate on the relevant symmetries and interactions of an emergent description [1]. Today, advances in nano and micro fabrication, characterization, and control, can invert that approach. We can realize artificial systems whose interacting, elementary degrees of freedom can be tailor-designed for exotic behaviors in their collective, low-energy kinetics. That is the case of artificial spin ice materials [2], which can now be variously manufactured in arrays of magnetic nano-islands [3], trapped colloids [4], vortices in nano-patterned superconductors [5], or possibly with skyrmions in liquid crystals. They can produce new phenomena often non seen in natural materials, such as complex kinetics of magnetic charges and magnetic monopoles [6], new forms of frustration [7], classical forms of topological order [8], dimensionality reduction [9], or ergodicity breaking in absence of quenched disorder. With the goal of eliciting contributions in this field by early career scientists and students we will briefly summarize the fiend and then report on the more recent results.

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[2] Wang, 1. RF, et al. Nature 439.7074 (2006): 303.

[3] Nisoli, Cristiano, et al. Reviews of Modern Physics 85.4 (2013): 1473.

[4] Ortiz-Ambriz, Antonio, and Pietro Tierno. Nature communications 7 (2016): 10575.

[5] Latimer, M. L., et al. Physical review letters 111.6 (2013): 067001.

[6] Zhang, Sheng, et al. Nature 500.7464 (2013): 553.

[7] Nisoli, Cristiano, et al. Nature Physics 13.3 (2017): 200.

[8] Lao, Yuyang, et al. Nature Physics 14 (2018): 723.

[9] Gilbert, Ian, et al. Nature Physics 12.2 (2016): 162.