Octahedral rotations trigger electronic and magnetic transitions in strontium manganate under volume expansion

Xu-Jing Li; Huaican Chen; Peng-Fei Liu; Juping Xu; Bao-Tian Wang; Wen Yin

doi:10.1088/1361-648X/ac0e6d

Octahedral rotations trigger electronic and magnetic transitions in strontium manganate under volume expansion

J Phys Condens Matter. 2021 Jul 12;33(36). doi: 10.1088/1361-648X/ac0e6d.

Authors

Xu-Jing Li^{1

2

3}, Huaican Chen^{1

2}, Peng-Fei Liu^{1

2}, Juping Xu^{1

2}, Bao-Tian Wang^{1

2

3

4}, Wen Yin^{1

2

3}

Affiliations

¹ Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, People's Republic of China.
² Spallation Neutron Source Science Center, Dongguan 523803, People's Republic of China.
³ University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
⁴ Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.

PMID: 34167105
DOI: 10.1088/1361-648X/ac0e6d

Abstract

The perovskite structure of manganate yields a series of intriguing physical properties. Based on the results of first-principles calculations, strontium manganate appears to undergo a magnetic phase transition and a metal-insulator transition-from antiferromagnetic insulator to ferromagnetic metal and then to ferromagnetic insulator-under isotropic volume expansion combined with oxygen octahedral distortions. Interestingly, the results show that increasing the Mn-O bond length and adding rotation of the oxygen octahedra can soften the breathing distortion and account for the insulator phase. We further build a simple model to explain such transitions. Due to electron transfer and the favoring of a hole state of ligandporbitals, the electron state transfer from2(t2g3)to2(eg1+t2g2)and then tot2g3eg1+(t2g3L̲1). Such rearrangement of charges is responsible for the transitions of its magnetic order and electronic structure. Furthermore, we calculate spin susceptibility under the bare conditions and random phase approximation. The magnetic order of the intermediate metal state of itinerant electrons behaves as a ferromagnetic.

Keywords: Peierls transition; density functional theory; magnetic order; tight-binding model; transitions.