arXiv subjects

Kemp Plumb

Publications and source records attributed to Kemp Plumb.

2 recordsLinked to original sources

arXiv2023

Double-$Q$ chiral stripe order in the anomalous Hall antiferromagnet CoNb$_3$S$_6$

We present fine momentum space resolution resonant elastic x-ray scattering measurements of the magnetic structure of the metallic antiferromagnet CoNb$_3$S$_6$. Using circular dichroism and full linear polarization analysis of the magnetic scattering, we reveal a non-coplanar double-$Q$ ($2Q$) order, with a non-collinear commensurate component and a long-wavelength incommensurate helical component. This $2Q$ structure exhibits a staggered scalar spin chirality that forms a modulated stripe-like pattern with no uniform component. This novel magnetic order is naturally explained by the presence of four-spin exchange interactions and exhibits a complex domain structure that suggests a lowering of the structural symmetry. A symmetry analysis indicates that the $2Q$ order enables a finite anomalous Hall effect in CoNb$_3$S$_6$. In addition to identifying a novel type of magnetic ordering and its origin, our results provide insight into the mechanism of the unconventional magnetotransport phenomena in CoNb$_3$S$_6$ and thus identifies potential routes for realizing novel electronic phenomena in metallic antiferromagnets.

cond-mat.str-el↗

arXiv2015

Automated three-dimensional single cell phenotyping of spindle dynamics, cell shape, and volume

We present feature finding and tracking algorithms in 3D in living cells, and demonstrate their utility to measure metrics important in cell biological processes. We developed a computational imaging hybrid approach that combines automated three-dimensional tracking of point-like features with surface determination from which cell (or nuclear) volume, shape, and planes of interest can be extracted. After validation, we applied the technique to real space context-rich dynamics of the mitotic spindle, and cell volume and its relationship to spindle length, in dividing living cells. These methods are additionally useful for automated segregation of pre-anaphase and anaphase spindle populations in budding yeast. We found that genetic deletion of the yeast kinesin-5 mitotic motor cin8 leads to large mother and daughter cells that were indistinguishable based on size, and that in those cells the spindle length becomes uncorrelated with cell size. The technique can be used to visualize and quantify tracked feature coordinates relative to cell bounding surface landmarks, such as the plane of cell division, and will enable for advancing studies of non-equilibrium processes in living cells.

physics.bio-ph↗