Title: Mott localization in a pure stripe antiferromagnet ${\mathrm{Rb}}_{1-\delta }{\mathrm{Fe}}_{1.5-\sigma }{\mathrm{S}}_2$

Abstract

A combination of neutron diffraction and angle-resolved photoemission spectroscopy measurements on a pure antiferromagnetic stripe $${\mathrm{Rb}}_{1{-}{\delta}}{\mathrm{Fe}}_{1.5{-}{\sigma}}{\mathrm{S}}_{2}$$ is reported here. A neutron diffraction experiment on a powder sample shows that a $98$% volume fraction of the sample is in the antiferromagnetic stripe phase with rhombic iron vacancy order and a refined composition of $${\mathrm{Rb}}_{0.66}{\mathrm{Fe}}_{1.36}{\mathrm{S}}_{2}$$, and that only $$2$$% of the sample is in the block antiferromagnetic phase with $$\sqrt{5}\times{}\sqrt{5}$$ iron vacancy order. Furthermore, a neutron diffraction experiment on a single crystal shows that there is only a single phase with the stripe antiferromagnetic order with the refined composition of $${\mathrm{Rb}}_{0.78}{\mathrm{Fe}}_{1.35}{\mathrm{S}}_{2}$$, while the phase with block antiferromagnetic order is absent. Angle-resolved photoemission spectroscopy measurements on the same crystal with the pure stripe phase reveal that the electronic structure is gapped at the Fermi level with a gap larger than 0.325 eV. The data collectively demonstrate that the extra $10$% iron vacancies in addition to the rhombic iron vacancy order effectively impede the formation of the block antiferromagnetic phase; the data also suggest that the stripe antiferromagnetic phase with rhombic iron vacancy order is a Mott insulator.

Authors:

Wang, Meng ^[1]; Yi, Ming ^[1]; Cao, Huibo ^[2]; de la Cruz, C. ^[2]; Mo, S. K. ^[3]; Huang, Q. Z. ^[4]; Bourret-Courchesne, E. ^[5]; Dai, Pengcheng ^[6]; Lee, D. H. ^[7]; Shen, Z. X. ^[8]; Birgeneau, R. J. ^[9]

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States). Dept. of Physics
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Condensed Matter Division
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source
4. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). NIST Center for Neutron Research
5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division
6. Rice Univ., Houston, TX (United States). Dept. of Physics and Astronomy
7. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division
8. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Inst. for Materials and Energy Sciences; Stanford Univ., CA (United States). Dept. of Physics and Applied Physics. Geballe Lab. for Advanced Materials
9. Univ. of California, Berkeley, CA (United States). Dept. of Physics. Dept. of Materials Science and Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division

Publication Date:

Tue Sep 01 00:00:00 EDT 2015

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1512245

Alternate Identifier(s):

OSTI ID: 1213754

Grant/Contract Number:  

AC02-05CH11231; SC0012311; AC02-76SF00515

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review. B, Condensed Matter and Materials Physics

Additional Journal Information:

Journal Volume: 92; Journal Issue: 12; Journal ID: ISSN 1098-0121

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY