The role of lattice dynamics in ferroelectric switching

Qiwu Shi; Eric Parsonnet; Xiaoxing Cheng; Natalya Fedorova; Ren-Ci Peng; Abel Fernandez; Alexander Qualls; Xiaoxi Huang; Xue Chang; Hongrui Zhang; David Pesquera; Sujit Das; Dmitri Nikonov; Ian Young; Long-Qing Chen; Lane W Martin; Yen-Lin Huang; Jorge Íñiguez; Ramamoorthy Ramesh

doi:10.1038/s41467-022-28622-z

The role of lattice dynamics in ferroelectric switching

Nat Commun. 2022 Mar 2;13(1):1110. doi: 10.1038/s41467-022-28622-z.

Authors

Qiwu Shi^#^{1

2}, Eric Parsonnet^#³, Xiaoxing Cheng^#⁴, Natalya Fedorova^#⁵, Ren-Ci Peng^{6

7}, Abel Fernandez⁸, Alexander Qualls³, Xiaoxi Huang⁸, Xue Chang⁹, Hongrui Zhang⁸, David Pesquera⁸, Sujit Das^{8

10}, Dmitri Nikonov¹¹, Ian Young¹¹, Long-Qing Chen⁴, Lane W Martin^{8

12}, Yen-Lin Huang^{13

14}, Jorge Íñiguez^{5

15}, Ramamoorthy Ramesh^{16

17

18}

Affiliations

¹ Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. shiqiwu@scu.edu.cn.
² College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China. shiqiwu@scu.edu.cn.
³ Department of Physics, University of California, Berkeley, CA, 94720, USA.
⁴ Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania, 16802, PA, USA.
⁵ Materials Research and Technology Department, Luxembourg Institute of Science and Technology, L-4362, Esch/Alzette, Luxembourg.
⁶ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Information and Engineering, Xi'an Jiaotong University, 710049, Xi'an, China.
⁷ School of Advanced Materials and Nanotechnology, Xidian University, Xi'an, 710126, China.
⁸ Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
⁹ College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, China.
¹⁰ Material Research Centre, Indian Institute of Science, Bangalore, 560012, India.
¹¹ Components Research, Intel Corporation, Hillsboro, OR, 97142, USA.
¹² Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
¹³ Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. yenlin.jack.huang@gmail.com.
¹⁴ Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan. yenlin.jack.huang@gmail.com.
¹⁵ Department of Physics and Materials Science, University of Luxembourg, L-4422, Belvaux, Luxembourg.
¹⁶ Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. rramesh@berkeley.edu.
¹⁷ Department of Physics, University of California, Berkeley, CA, 94720, USA. rramesh@berkeley.edu.
¹⁸ Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. rramesh@berkeley.edu.

^# Contributed equally.

Abstract

Reducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO₃) membranes and films clamped to a substrate. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO₃ films, to large (10's of micrometers) 180° domains in freestanding films. By removing the constraints imposed by mechanical clamping from the substrate, we can realize a ~40% reduction of the switching voltage and a consequent ~60% improvement in the switching speed. Our findings highlight the importance of a dynamic clamping process occurring during switching, which impacts strain, ferroelectric, and ferrodistortive order parameters and plays a critical role in setting the energetics and dynamics of ferroelectric switching.