Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Hang Chi; Yunbo Ou; Tim B Eldred; Wenpei Gao; Sohee Kwon; Joseph Murray; Michael Dreyer; Robert E Butera; Alexandre C Foucher; Haile Ambaye; Jong Keum; Alice T Greenberg; Yuhang Liu; Mahesh R Neupane; George J de Coster; Owen A Vail; Patrick J Taylor; Patrick A Folkes; Charles Rong; Gen Yin; Roger K Lake; Frances M Ross; Valeria Lauter; Don Heiman; Jagadeesh S Moodera

doi:10.1038/s41467-023-38995-4

Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

Nat Commun. 2023 Jun 3;14(1):3222. doi: 10.1038/s41467-023-38995-4.

Authors

Hang Chi^{1

2}, Yunbo Ou³, Tim B Eldred⁴, Wenpei Gao⁴, Sohee Kwon⁵, Joseph Murray⁶, Michael Dreyer⁶, Robert E Butera⁷, Alexandre C Foucher⁸, Haile Ambaye⁹, Jong Keum^{9

10}, Alice T Greenberg¹¹, Yuhang Liu⁵, Mahesh R Neupane^{11

5}, George J de Coster¹¹, Owen A Vail¹¹, Patrick J Taylor¹¹, Patrick A Folkes¹¹, Charles Rong¹¹, Gen Yin¹², Roger K Lake⁵, Frances M Ross⁸, Valeria Lauter⁹, Don Heiman^{13

14}, Jagadeesh S Moodera^{15

16}

Affiliations

¹ Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. chihang@mit.edu.
² DEVCOM Army Research Laboratory, Adelphi, MD, 20783, USA. chihang@mit.edu.
³ Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. ybou@mit.edu.
⁴ Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
⁵ Department of Electrical and Computer Engineering, University of California, Riverside, CA, 92521, USA.
⁶ Department of Physics, University of Maryland, College Park, MD, 20742, USA.
⁷ Laboratory for Physical Sciences, College Park, MD, 20740, USA.
⁸ Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
⁹ Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹⁰ Center for Nanophase Materials Sciences, Physical Science Directorate, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹¹ DEVCOM Army Research Laboratory, Adelphi, MD, 20783, USA.
¹² Department of Physics, Georgetown University, Washington, DC, 20057, USA.
¹³ Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
¹⁴ Department of Physics, Northeastern University, Boston, MA, 02115, USA.
¹⁵ Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. moodera@mit.edu.
¹⁶ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. moodera@mit.edu.

Abstract

Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in pristine Cr₂Te₃ thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations. The sign change is strain tunable, enabled by the sharp and well-defined substrate/film interface in the quasi-two-dimensional Cr₂Te₃ epitaxial films, revealed by scanning transmission electron microscopy and depth-sensitive polarized neutron reflectometry. This Berry phase effect further introduces hump-shaped Hall peaks in pristine Cr₂Te₃ near the coercive field during the magnetization switching process, owing to the presence of strain-modulated magnetic layers/domains. The versatile interface tunability of Berry curvature in Cr₂Te₃ thin films offers new opportunities for topological electronics.

Grants and funding

W911NF-19-2-0015/United States Department of Defense | United States Army | U.S. Army Research, Development and Engineering Command | Army Research Laboratory (U.S. Army Research Laboratory)