When twisted close to a magic relative orientation angle near 1 degree, bilayer graphene has flat moire superlattice minibands that have emerged as a rich and highly tunable source of strong correlation physics, notably the appearance of superconductivity close to interaction-induced insulating states. Here we report on the fabrication of bilayer graphene devices with exceptionally uniform twist angles. We show that the reduction in twist angle disorder reveals insulating states at all integer occupancies of the four-fold spin/valley degenerate flat conduction and valence bands, i.e. at moire band filling factors nu = 0, +(-) 1, +(-) 2, +(-) 3, and reveals new superconductivity regions below critical temperatures as high as 3 K close to – 2 filling. In addition we find novel orbital magnetic states with non-zero Chern numbers. Our study shows that symmetry-broken states, interaction driven insulators, and superconducting domes are common across the entire moire flat bands, including near charge neutrality. We further will discuss recent experiments including screened interactions, fragile topology and the first applications of this amazing new materials platform.
Pour assiter à ce séminaire dématérialisé, veuillez suivre le lien suivant: Join Zoom Meeting
https://zoom.us/j/97994785592?pwd=Q1hZR0U4OGFOSXh2bS9iRFo4V2MvUT09
Meeting ID: 979 9478 5592
Passcode: Gsg522
Dial by your location +33 1 7095 0350 France
+33 1 8699 5831 France
+33 1 7037 2246 France
+33 1 7037 9729 France
+33 1 7095 0103 France
+34 91 787 0058 Spain
+34 917 873 431 Spain
+34 84 368 5025 Spain
Meeting ID: 979 9478 5592 Passcode: 662780
MPQ Univ. de Paris