[17a-A35-1~9] 4.5 Nanocarbon and 2D Materials

10:00 〜 10:30英語発表注目講演

[17a-A35-4] [JSAP-Optica Joint Symposia Invited Talk] Electronic and excitonic properties of semiconductor bilayer moiré system revealed by optical spectroscopy

〇Yuya Shimazaki^1,2 (1.RIKEN, CEMS, 2.Univ. of Tokyo, Eng.)

キーワード：

transition metal dichalcogenide、moire superlattice、strongly correlated electrons

We studied a twisted bilayer MoSe₂ system with monolayer hBN tunnel barrier via optical microscopic spectroscopy. The combination of the top and bottom gates allows to control the chemical potential and the perpendicular electric field independently. The energy shifts of excitonic resonances probe the carrier densities of the top and bottom layers independently, which revealed the formation of moiré sub bands in the system. By changing the energy detuning between layers via control of the perpendicular electric field, we observed an abrupt charge transfer at ν = 1 (1 electron per moiré lattice) and a stabilized charge transfer plateau at ν = 2 around zero detuning point, which evidences the existence of strongly correlated electrons. We further observed the existence of charge order at these fillings from the Umklapp scattering of excitons. Last but not least, we figured out that the tunnel coupling of holes through the monolayer hBN barrier results in formation of hybrid exciton states and electric field-controlled exciton – hole Feshbach resonances.