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DOE OSTI · 3384955

Block-Type Antiferromagnetism in Single Chain Quasi-One-Dimensional K 3 ⁢Fe 2 ⁢Se 4

Gao, Fei [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000292263996)·Dhale, Nikhil [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0009000313859359)·Lin, Ling-Fang [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000300456537)·Taddei, Keith M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000214680823)·Zhang, Yang [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000336235883)·Cruz, Clarina Dela [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000342332145)·Dagotto, Elbio [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000160075694)·Lv, Bing [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000294915177)
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Abstract

One-dimensional (1D) structures provide a unique platform to study the correlated quantum interactions and phase transitions such as unconventional magnetism and superconducting states. Here, we report that iron chalcogenide K 3 ⁢Fe 2 ⁢Se 4 exhibits an unusual block-type canted antiferromagnetic (AFM) order with a clear single chain quasi-1D structure, which is structurally different from the two-leg ladder BaFe 2 ⁢Se 3 , through both experimental measurements and density matrix renormalization group (DMRG) calculations. The narrow bandgap semiconductor K 3 ⁢Fe 2 ⁢Se 4 has a quasi-1D edge-shared FeSe4 tetrahedra chain structure and orders antiferromagnetically below 110 K. The magnetic moments couple antiferromagnetically along the quasi-1D chain direction of the 𝑏 axis and form an up-down-down-up (↑−↓−↓−↑)–like spin structure with a commensurate propagation vector 𝒌=⁢(0,0,0), where block-type spin ↑−↑ or ↓−↓ coupling are between the longer Fe-Fe bonds of the quasi-1D chain. DMRG results show that block antiferromagnetic state is stable in K 3 ⁢Fe 2 ⁢Se 4 and reveal that the block-ordered arrangement of Fe 2.5+ ions spins arise from the competition between ferromagnetic and AFM interaction in the presence of strong electronic correlation. Our research results not only report the discovery of a clear block-type canted antiferromagnetic structure in a real quasi-1D chain material but also provide a theoretical approach to understand the block-type antiferromagnetism in quasi-1D iron chalcogenides.

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antiferromagnetismdensity matrix renormalization groupexchange interactionmagnetic ordermagnetic phase transitions

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Gao, Fei [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000292263996), Dhale, Nikhil [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0009000313859359), Lin, Ling-Fang [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000300456537), Taddei, Keith M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)] (ORCID:0000000214680823), Zhang, Yang [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000336235883), Cruz, Clarina Dela [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000342332145), Dagotto, Elbio [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000160075694), Lv, Bing [Univ. of Texas at Dallas, Richardson, TX (United States)] (ORCID:0000000294915177). 2026-06-24. Block-Type Antiferromagnetism in Single Chain Quasi-One-Dimensional K 3 ⁢Fe 2 ⁢Se 4. https://doi.org/10.1103/g8zx-gc2t

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