Symmetry and simplicity spontaneously emerge from the algorithmic nature of evolution
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 119:11 (2022) ARTN e2113883119
The interplay of supercoiling and thymine dimers in DNA
NUCLEIC ACIDS RESEARCH 50:5 (2022) ARTN gkac082
Learning developmental mode dynamics from single-cell trajectories
eLife eLife 10 (2021) e68679
Multi-k spin ordering in CaFe3Ti4O12 stabilized by spin-orbit coupling and further-neighbor exchange
Physical Review Research American Physical Society 3:4 (2021) 043208
Abstract:
Orthogonal spin ordering is rarely observed in magnetic oxides because nearest-neighbor symmetric Heisenberg superexchange interactions usually dominate. We have discovered that in the quadruple perovskite CaFe3Ti4O12, where only the S=2 Fe2+ ion is magnetic, long-range magnetic order consisting of an unusual arrangement of three interpenetrating orthogonal sublattices is stabilized. Each magnetic sublattice corresponds to a set of FeO4 square planes sharing a common orientation. This multi-k magnetic spin ordering is the result of fourth-neighbor spin couplings with a strong easy-axis anisotropy. In an applied magnetic field, each sublattice tends towards ferromagnetic alignment, but remains polarized by internal magnetic fields generated by the others, thus stabilizing in a noncollinear canted ferromagnetic structure. CaFe3Ti4O12 provides a rare example of how nontrivial long-range spin order can arise when near-neighbor Heisenberg superexchange is quenched.Interview with Ramin Golestanian: Living Matter, or What Is Life?
Chapter in Active Materials, De Gruyter (2021) 157-172