Title: Sequential structural and antiferromagnetic transitions in ${\mathrm{BaFe}}_2{\mathrm{Se}}_3$ under pressure

Abstract

We present the discovery of superconductivity in the two-leg ladder compound BaFe ₂S ₃ has established the 123-type iron chalcogenides as a novel and interesting subgroup of the iron-based superconductor family. However, in this 123 series, BaFe ₂Se ₃ is an exceptional member, with a magnetic order and crystalline structure different from all others. Recently, an exciting experiment reported the emergence of superconductivity in BaFe ₂Se ₃ at high pressure [J. Ying et al., Phys. Rev. B 95, 241109(R) (2017)]. In this paper, we report a first-principles study of BaFe ₂Se ₃. Our analysis unveils a variety of qualitative differences between BaFe ₂S ₃ and BaFe ₂Se ₃, including in the latter an unexpected chain of transitions with increasing pressure. First, by gradually reducing the tilting angle of iron ladders, the crystalline structure smoothly transforms from Pnma to Cmcm at ~6 GPa. Second, the system becomes metallic at 10.4 GPa. Third, its unique ambient-pressure Block antiferromagnetic ground state is replaced by the more common stripe (so-called CX-type) antiferromagnetic order at ~12 GPa, the same magnetic state as the 123-S ladder. This transition is found at a pressure very similar to the experimental superconducting transition. Finally, all magnetic moments vanish atmore » 30 GPa. This reported theoretical diagram of the complete phase evolution is important because of the technical challenges to capture many physical properties in high-pressure experiments. The information obtained in our calculations suggests different characteristics for superconductivity in BaFe ₂Se ₃ and BaFe ₂S ₃: in 123-S pairing occurs when magnetic moments vanish, while in 123-Se the transition region from Block- to CX-type magnetism appears to catalyze superconductivity. Lastly, an additional superconducting dome above ~30 GPa is expected to occur.« less

Authors:

Zhang, Yang ^[1]; Lin, Ling-Fang ^[1]; Zhang, Jun-Jie ^[1]; Dagotto, Elbio R. ^[2]; Dong, Shuai ^[1]

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+ Show Author Affiliations

1. Southeast Univ., Nanjing (China). School of Physics
2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

Publication Date:

2018-01-16

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1422584

Alternate Identifier(s):

OSTI ID: 1417069

Grant/Contract Number:  

AC05-00OR22725; KYCX17_0047

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 97; Journal Issue: 4; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE