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Local optical control of ferromagnetism and chemical potential in a topological insulator
- Source :
- PNAS 114 (39) 10379-10383 (2017)
- Publication Year :
- 2017
-
Abstract
- Many proposed experiments involving topological insulators (TIs) require spatial control over time-reversal symmetry and chemical potential. We demonstrate reconfigurable micron-scale optical control of both magnetization (which breaks time-reversal symmetry) and chemical potential in ferromagnetic thin films of Cr-(Bi,Sb)$_2$Te$_3$ grown on SrTiO$_3$. By optically modulating the coercivity of the films, we write and erase arbitrary patterns in their remanent magnetization, which we then image with Kerr microscopy. Additionally, by optically manipulating a space charge layer in the underlying SrTiO$_3$ substrates, we control the local chemical potential of the films. This optical gating effect allows us to write and erase p-n junctions in the films, which we study with photocurrent microscopy. Both effects are persistent and may be patterned and imaged independently on a few-micron scale. Dynamic optical control over both magnetization and chemical potential of a TI may be useful in efforts to understand and control the edge states predicted at magnetic domain walls in quantum anomalous Hall insulators.<br />Comment: 15 pages, 5 figures
Details
- Database :
- arXiv
- Journal :
- PNAS 114 (39) 10379-10383 (2017)
- Publication Type :
- Report
- Accession number :
- edsarx.1704.00831
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1073/pnas.1713458114