Large-Area Intercalated Two-Dimensional Pb/Graphene Heterostructure as a Platform for Generating Spin-Orbit Torque

Alexander Vera; Boyang Zheng; Wilson Yanez; Kaijie Yang; Seong Yeoul Kim; Xinglu Wang; Jimmy C Kotsakidis; Hesham El-Sherif; Gopi Krishnan; Roland J Koch; T Andrew Bowen; Chengye Dong; Yuanxi Wang; Maxwell Wetherington; Eli Rotenberg; Nabil Bassim; Adam L Friedman; Robert M Wallace; Chaoxing Liu; Nitin Samarth; Vincent H Crespi; Joshua A Robinson

doi:10.1021/acsnano.4c04075

Large-Area Intercalated Two-Dimensional Pb/Graphene Heterostructure as a Platform for Generating Spin-Orbit Torque

ACS Nano. 2024 Aug 20;18(33):21985-21997. doi: 10.1021/acsnano.4c04075. Epub 2024 Aug 5.

Authors

Alexander Vera^{1

2}, Boyang Zheng^{3

4}, Wilson Yanez^{2

3}, Kaijie Yang^{2

3}, Seong Yeoul Kim⁵, Xinglu Wang⁵, Jimmy C Kotsakidis⁶, Hesham El-Sherif⁷, Gopi Krishnan⁷, Roland J Koch⁸, T Andrew Bowen^{1

2}, Chengye Dong^{4

9}, Yuanxi Wang⁴, Maxwell Wetherington¹⁰, Eli Rotenberg⁸, Nabil Bassim^{7

11}, Adam L Friedman⁶, Robert M Wallace⁵, Chaoxing Liu^{2

3}, Nitin Samarth^{2

3

4

9}, Vincent H Crespi^{1

2

3

4

9

10

12}, Joshua A Robinson^{1

2

3

4

9

10

12

13}

Affiliations

¹ Department of Materials Science and Engineering, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.
² Center for Nanoscale Science, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.
³ Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
⁴ 2-Dimensional Crystal Consortium, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.
⁵ Department of Materials Science and Engineering, The University of Texas at Dallas, Dallas ,Texas 75080, United States.
⁶ Laboratory for Physical Sciences, College Park, College Park ,Maryland 20740, United States.
⁷ Department of Materials Science and Engineering, McMaster University, Hamilton ,Ontario L8S 4L8, Canada.
⁸ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
⁹ Center for 2-Dimensional and Layered Materials, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.
¹⁰ Materials Research Institute, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.
¹¹ Canadian Centre for Electron Microscopy, McMaster University, Hamilton ,Ontario L8S 4M1, Canada.
¹² Department of Chemistry, The Pennsylvania State University, University Park ,Pennsylvania 18802, United States.
¹³ Center for Atomically Thin Multifunctional Coatings, The Pennsylvania State University, University Park ,Pennsylvania 16802, United States.

PMID: 39102316
DOI: 10.1021/acsnano.4c04075

Abstract

A scalable platform to synthesize ultrathin heavy metals may enable high-efficiency charge-to-spin conversion for next-generation spintronics. Here, we report the synthesis of air-stable, epitaxially registered monolayer Pb underneath graphene on SiC (0001) by confinement heteroepitaxy (CHet). Diffraction, spectroscopy, and microscopy reveal that CHet-based Pb intercalation predominantly exhibits a mottled hexagonal superstructure due to an ordered network of Frenkel-Kontorova-like domain walls. The system's air stability enables ex situ spin torque ferromagnetic resonance (ST-FMR) measurements that demonstrate charge-to-spin conversion in graphene/Pb/ferromagnet heterostructures with a 1.5× increase in the effective field ratio compared to control samples.

Keywords: 2D metals; Frenkel−Kontorova; confinement heteroepitaxy; monolayer Pb; spintronics.