Broken symmetry is a fundamental concept prevailing in many branches of physics. The physical properties of a crystalline solid are intimately linked to its symmetry. Any broken symmetry in the solid is likewise consequential. B20 chiral materials have a simple cubic unit cell. However, the basis within the cubic unit cell breaks the inversion symmetry and the 4-fold (C4) rotation symmetry. The broken inversion symmetry leads to the Dzyaloshinskii-Moriya (D-M) interaction that leads to magnetic skyrmions in B20 magnets. We reveal unusual anisotropic magnetoresistance (AMR) of B20 magnets as a consequence of broken C4 rotation symmetry. We also observe greatly extended skyrmion phase in epitaxial FeGe films.
Very recently, B20 materials (MnSi and CoSi) have been reported to exhibit unusual band topology with emergence of chiral fermions and topological nodal planes. |
Relevant publications
1. Spin phases of the helimagnetic insulator Cu2OSeO3 probed by magnon heat conduction, N. Prasai, A. Akopyan, B. A. Trump, G. G. Marcus, S. X. Huang, T. M. McQueen, and J. L. Cohn, Physical Review B (rapid communication), 99, 020403 (R) (2019).
2. Precipitating ordered skyrmion lattices from helical spaghetti, Dustin A. Gilbert, Alexander J. Grutter, Paul Neves, G. J. Shu, Gergely Zimanyi, Brian B. Maranville, F. C. Chou, Kathryn Krycka, Nicholas Butch, S. X. Huang, and Julie A. Borchers, Physical Review Materials, 3, 014408 (2019).
3. Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu2OSeO3, N. Prasai, B. A. Trump, G. G. Marcus, A. Akopyan, S. X. Huang, T. L. McQueen, and J. L. Cohn, Physical Review B (Editors’ Suggestion) 95, 224407 (2017).
4. Unusual Magnetoresistance in Cubic B20 Fe0.85Co0.15Si Chiral Magnets, S. X. Huang, Fei Chen, Jian Kang, Jiadong Zang, G. J. Shu, F. C. Chou, and C. L. Chien, (invited) New Journal of Physics (Focus on Magnetic Skyrmions) 18, 065010 (2016).
5. Universal Ratio of Intrinsic Resistivities of Spin Helix in B20 (Fe-Co)Si Magnets, S. X. Huang, J. Kang, F. Chen, J. Zang, G. J. Shu, F. C. Chou, S. V. Grigoriev, V. A. Dyadkin, and C. L. Chien. arXiv:1409.7869 [cond-mat] (2014).
6. Extended Skyrmion Phase in Epitaxial FeGe(111) Thin Films, S. X. Huang, and C. L. Chien, Physical Review Letters 108, 267201 (2012).
2. Precipitating ordered skyrmion lattices from helical spaghetti, Dustin A. Gilbert, Alexander J. Grutter, Paul Neves, G. J. Shu, Gergely Zimanyi, Brian B. Maranville, F. C. Chou, Kathryn Krycka, Nicholas Butch, S. X. Huang, and Julie A. Borchers, Physical Review Materials, 3, 014408 (2019).
3. Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu2OSeO3, N. Prasai, B. A. Trump, G. G. Marcus, A. Akopyan, S. X. Huang, T. L. McQueen, and J. L. Cohn, Physical Review B (Editors’ Suggestion) 95, 224407 (2017).
4. Unusual Magnetoresistance in Cubic B20 Fe0.85Co0.15Si Chiral Magnets, S. X. Huang, Fei Chen, Jian Kang, Jiadong Zang, G. J. Shu, F. C. Chou, and C. L. Chien, (invited) New Journal of Physics (Focus on Magnetic Skyrmions) 18, 065010 (2016).
5. Universal Ratio of Intrinsic Resistivities of Spin Helix in B20 (Fe-Co)Si Magnets, S. X. Huang, J. Kang, F. Chen, J. Zang, G. J. Shu, F. C. Chou, S. V. Grigoriev, V. A. Dyadkin, and C. L. Chien. arXiv:1409.7869 [cond-mat] (2014).
6. Extended Skyrmion Phase in Epitaxial FeGe(111) Thin Films, S. X. Huang, and C. L. Chien, Physical Review Letters 108, 267201 (2012).