Spin transport in a Mott insulator of ultracold fermions

Matthew A Nichols; Lawrence W Cheuk; Melih Okan; Thomas R Hartke; Enrique Mendez; T Senthil; Ehsan Khatami; Hao Zhang; Martin W Zwierlein

doi:10.1126/science.aat4387

Spin transport in a Mott insulator of ultracold fermions

Science. 2019 Jan 25;363(6425):383-387. doi: 10.1126/science.aat4387. Epub 2018 Dec 6.

Authors

Matthew A Nichols^{1

2

3}, Lawrence W Cheuk^{2

4}, Melih Okan^{1

2

3}, Thomas R Hartke^{1

2

3}, Enrique Mendez^{1

2

3}, T Senthil¹, Ehsan Khatami⁵, Hao Zhang^{1

2

3}, Martin W Zwierlein^{6

2

3}

Affiliations

¹ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
² MIT-Harvard Center for Ultracold Atoms, Cambridge, MA 02139, USA.
³ Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
⁴ Department of Physics, Harvard University, Cambridge, MA 02138, USA.
⁵ Department of Physics and Astronomy, San José State University, San José, CA 95192, USA.
⁶ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. zwierlein@mit.edu.

PMID: 30523079
DOI: 10.1126/science.aat4387

Abstract

Strongly correlated materials are expected to feature unconventional transport properties, such that charge, spin, and heat conduction are potentially independent probes of the dynamics. In contrast to charge transport, the measurement of spin transport in such materials is highly challenging. We observed spin conduction and diffusion in a system of ultracold fermionic atoms that realizes the half-filled Fermi-Hubbard model. For strong interactions, spin diffusion is driven by super-exchange and doublon-hole-assisted tunneling, and strongly violates the quantum limit of charge diffusion. The technique developed in this work can be extended to finite doping, which can shed light on the complex interplay between spin and charge in the Hubbard model.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.