Calendar

ICMT Seminar: "Moiré interference of atomic arrangement"

Speaker Dr Pilkyng Moon from NewYork University, Shanghai
Date: 4/4/2017
Time: 10 a.m.
Location:

3110 ESB

Sponsor:

Institute for Condensed Matter Physics

Event Type: Seminar/Symposium
 

When repetitive structures are overlaid against each other, a new superimposed moiré pattern emerges and is observed in various macroscopic phenomena. Likewise, in case the lattice periods do not coincide between atomically thin layers, the moiré interference between the lattices makes a new class of superlattices where the influence of the exceptionally long-period interlayer interaction is crucial to determine its electronic structures [1, 2].

 

  In this talk, I will first discuss the impact of two-dimensional moiré superlattice formation for graphene systems and for hybrid layered-structures, and show that their electronic and optical properties are significantly altered if compared with those of the pristine graphene [1, 3]. Then, I will show that the moiré superlattice affords a unique opportunity to study the fundamental problem on the motions of electrons under the simultaneous influence of a periodic potential and a magnetic field in the normally inaccessible regime of quantum Hall effect, aka Hofstadter’s butterfly [4]. The non-monotonic behavior of quantized Hall conductivity [5] and the nesting of optical selection rule in the fractal energy spectrum will be discussed [6]. And we will show that aperiodic multi-walled nanotubes can be classified into one-dimensional moiré crystals with distinct electronic structures. Even the combination of single-walled nanotubes with almost the same physical properties can end up with very different superlattices depending on the interlayer moiré interference.

 

References

[1] P. Moon and M. Koshino, Phys. Rev. B 87, 205404 (2013).

[2] M. Koshino, P. Moon, and Y.-W. Son, Phys. Rev. B 91, 035405 (2015).

[3] P. Moon and M. Koshino, Phys. Rev. B 90, 155406 (2014).

[4] P. Moon and M. Koshino, Phys. Rev. B 85, 195458 (2012).

[5] C. R. Dean et al., Nature 497, 598 (2013); B. Hunt et al., Science 340, 1427 (2013).

[6] P. Moon and M. Koshino, Phys. Rev. B 88, 241412(R) (2013).

 

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