Apr 24, 2024
10:30am - 10:45am
Room 436, Level 4, Summit
Sampath Gamage1,Sukriti Manna2,Marc Zajac2,Steven Hancock1,Qi Wang3,Sarabpreet Singh1,Mahdi Ghafariasl1,Kun Yao1,Tom Tiwald4,Tae Joon Park3,David Landau1,Haidan Wen2,Subramanian Sankaranarayanan2,Pierre Darancet2,Shriram Ramanathan5,Yohannes Abate1
University of Georgia1,Argonne National Laboratory2,Purdue University3,J. A. Woollam Inc.4,Rutgers, The State University of New Jersey5
Sampath Gamage1,Sukriti Manna2,Marc Zajac2,Steven Hancock1,Qi Wang3,Sarabpreet Singh1,Mahdi Ghafariasl1,Kun Yao1,Tom Tiwald4,Tae Joon Park3,David Landau1,Haidan Wen2,Subramanian Sankaranarayanan2,Pierre Darancet2,Shriram Ramanathan5,Yohannes Abate1
University of Georgia1,Argonne National Laboratory2,Purdue University3,J. A. Woollam Inc.4,Rutgers, The State University of New Jersey5
Solid-state devices from correlated oxides such as perovskite nickelates are promising for neuromorphic computing by mimicking biological synaptic function. However, comprehending dopant action at the nanoscale poses a formidable challenge to understanding the elementary mechanisms involved. Here, we perform operando infrared nanoimaging of hydrogen-doped correlated perovskite, neodymium nickel oxide (H-NdNiO<sub>3</sub>) devices and reveal how an applied field perturbs dopant distribution at the nanoscale. This perturbation leads to stripe phases of varying conductivity perpendicular to the applied field, which defines the macroscale electrical characteristics of the devices. Hyperspectral nano-FTIR imaging with density functional theory calculations unveils a real-space map of multiple vibrational states of H-NNO associated with OH stretching modes and their dependence on the dopant concentration. Moreover, the localization of excess charges induces an out-of-plane lattice expansion in NNO which was confirmed by in-situ - x-ray diffraction and creates a strain that acts as a barrier against further diffusion. Our results and the techniques presented here hold great potential in the rapidly growing field of memristors and neuromorphic devices wherein nanoscale ion motion is fundamentally responsible for function.