The persistence of memory in ionic conduction probed by nonlinear optics

Andrey D Poletayev; Matthias C Hoffmann; James A Dawson; Samuel W Teitelbaum; Mariano Trigo; M Saiful Islam; Aaron M Lindenberg

doi:10.1038/s41586-023-06827-6

The persistence of memory in ionic conduction probed by nonlinear optics

Nature. 2024 Jan;625(7996):691-696. doi: 10.1038/s41586-023-06827-6. Epub 2024 Jan 24.

Authors

Andrey D Poletayev^{1

2

3}, Matthias C Hoffmann⁴, James A Dawson^{5

6}, Samuel W Teitelbaum^{7

8

9}, Mariano Trigo^{7

8}, M Saiful Islam^{10

11}, Aaron M Lindenberg^{12

13

14}

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory, Menlo Park, CA, USA. andrey.poletayev@gmail.com.
² Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. andrey.poletayev@gmail.com.
³ Department of Materials, University of Oxford, Oxford, UK. andrey.poletayev@gmail.com.
⁴ Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁵ Chemistry, School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK.
⁶ Centre for Energy, Newcastle University, Newcastle upon Tyne, UK.
⁷ Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory, Menlo Park, CA, USA.
⁸ Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁹ Department of Physics, Arizona State University, Tempe, AZ, USA.
¹⁰ Department of Materials, University of Oxford, Oxford, UK.
¹¹ Department of Chemistry, University of Bath, Bath, UK.
¹² Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory, Menlo Park, CA, USA. aaronl@stanford.edu.
¹³ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. aaronl@stanford.edu.
¹⁴ Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. aaronl@stanford.edu.

Abstract

Predicting practical rates of transport in condensed phases enables the rational design of materials, devices and processes. This is especially critical to developing low-carbon energy technologies such as rechargeable batteries^1-3. For ionic conduction, the collective mechanisms^4,5, variation of conductivity with timescales^6-8 and confinement^9,10, and ambiguity in the phononic origin of translation^11,12, call for a direct probe of the fundamental steps of ionic diffusion: ion hops. However, such hops are rare-event large-amplitude translations, and are challenging to excite and detect. Here we use single-cycle terahertz pumps to impulsively trigger ionic hopping in battery solid electrolytes. This is visualized by an induced transient birefringence, enabling direct probing of anisotropy in ionic hopping on the picosecond timescale. The relaxation of the transient signal measures the decay of orientational memory, and the production of entropy in diffusion. We extend experimental results using in silico transient birefringence to identify vibrational attempt frequencies for ion hopping. Using nonlinear optical methods, we probe ion transport at its fastest limit, distinguish correlated conduction mechanisms from a true random walk at the atomic scale, and demonstrate the connection between activated transport and the thermodynamics of information.