Direct observation of delithiation as the origin of analog memristance in Li x NbO 2

DOI: 10.1063/1.5108525

Authors: Sebastian A. Howard (Binghamton University) , Christopher N. Singh (Binghamton University) , Galo J. Paez (Binghamton University) , Matthew Wahila (Binghamton University) , Linda W. Wangoh (Binghamton University) , Shawn Sallis (Binghamton University) , Keith Tirpak (Binghamton University) , Yufeng Liang (The Molecular Foundry, Lawrence Berkeley National Laboratory) , David Prendergast (The Molecular Foundry, Lawrence Berkeley National Laboratory) , Mateusz Zuba (Binghamton University) , Jatinkumar Rana (Binghamton University) , Alex Weidenbach (Georgia Institute of Technology) , Timothy M. Mccrone (Georgia Institute of Technology) , Wanli Yang (Advanced Light Source) , Tien-lin Lee (Diamond Light Source) , Fanny Rodolakis (Argonne National Laboratory) , William Doolittle (Georgia Institute of Technology) , Wei-cheng Lee (Binghamton University) , Louis F. J. Piper (Binghamton University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Apl Materials , VOL 7

State: Published (Approved)
Published: July 2019
Diamond Proposal Number(s): 20647

Abstract: The discovery of analog LixNbO2 memristors revealed a promising new memristive mechanism wherein the diffusion of Li+ rather than O2− ions enables precise control of the resistive states. However, directly correlating lithium concentration with changes to the electronic structure in active layers remains a challenge and is required to truly understand the underlying physics. Chemically delithiated single crystals of LiNbO2 present a model system for correlating lithium variation with spectroscopic signatures from operando soft x-ray spectroscopy studies of device active layers. Using electronic structure modeling of the x-ray spectroscopy of LixNbO2 single crystals, we demonstrate that the intrinsic memristive behavior in LixNbO2 active layers results from field-induced degenerate p-type doping. We show that electrical operation of LixNbO2-based memristors is viable even at marginal Li deficiency and that the analog memristive switching occurs well before the system is fully metallic. This study serves as a benchmark for material synthesis and characterization of future LixNbO2-based memristor devices and suggests that valence change switching is a scalable alternative that circumvents the electroforming typically required for filamentary-based memristors.

Journal Keywords: Semiconductors; Density functional theory; X-ray diffraction; Transition metals; X-ray photoelectron spectroscopy; X-ray absorption spectroscopy; Memristor

Subject Areas: Physics, Materials


Instruments: I09-Surface and Interface Structural Analysis

Other Facilities: Advanced Photon Source

Documents:
mem44.pdf