NCTS (South)



PLACER49223, Second Physics Building , NCKU

FIELDQuantum Information Science

SPEAKER Prof. Chi-Ken Lu - 台灣師範大學

TITLEVan Hove Singularity and magnetic breakdown in two-dimensional Dirac system

ABSTRACTIn two-dimensional solids there are critical points in band structure showing logarithmic divergence in density of state. These critical points occur when different bands start to overlap with each other. There are predictions that in the vicinity of such critical point the interaction between electrons are enhanced. Examples include the high-Tc superconductors and the doped graphene. Therefore to probe this critical point in band structure is important. In this talk, I shall introduce the twisted bilayer graphene in which the critical energy is relatively low and accessible. In the presence of magnetic field, the classical cyclotron motion for electrons are strongly modified by the critical points, which leads to a rather different Landau level spectrum.

Reference [1] CKL and H.A. Fertig, Magnetic breakdown in twisted bilayer graphene, PRB 89 085408 (2014)
[2] CKL and H.A. Fertig, Probing layer delocalization in twisted bilayer graphene via cyclotron resonance, PRB 90 115436 (2014).