title: Predicted Quantum Topological Hall Effect and Noncoplanar Antiferromagnetism in K_{0.5}RhO_{2}.
abstract: The quantum anomalous Hall (QAH) phase is a two-dimensional bulk ferromagnetic insulator with a nonzero Chern number in the presence of spin-orbit coupling (SOC) but in the absence of applied magnetic fields. Associated metallic chiral edge states host dissipationless current transport in electronic devices. This intriguing QAH phase has recently been observed in magnetic impurity-doped topological insulators, albeit, at extremely low temperatures. Based on first-principles density functional calculations, here we predict that layered rhodium oxide K_{0.5}RhO_{2} in the noncoplanar chiral antiferromagnetic state is an unconventional three-dimensional QAH insulator with a large band gap and a Néel temperature of a few tens of Kelvins. Furthermore, this unconventional QAH phase is revealed to be the exotic quantum topological Hall effect caused by nonzero scalar spin chirality due to the topological spin structure in the system and without the need of net magnetization and SOC.
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Physics, Shaoxing University, Shaoxing 312000, China.
authors.forename: Qi-Feng
authors.initials: QF
authors.lastname: Liang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Hongming
authors.initials: H
authors.lastname: Weng
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Y B
authors.initials: YB
authors.lastname: Chen
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Yao
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China.|Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
authors.forename: Yan-Feng
authors.initials: YF
authors.lastname: Chen
authors.affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Jinming
authors.initials: J
authors.lastname: Dong
authors.affiliation: Department of Physics, National Taiwan University, Taipei 10617, Taiwan.|Physics Division, National Center for Theoretical Sciences, Hsinchu 30013, Taiwan.
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Guo