Harvard Quantum Initiative Special Seminar

Friday, August 30

11:00 AM

Jefferson 356

Yonglong Xie (Princeton)

Spectroscopic signatures of many-body correlations in magic-angle twisted bilayer graphene
The discovery of superconducting and insulating states in magic-angle twisted bilayer graphene (MATBG) [1,2] has ignited considerable interest in understanding the nature of electronic interactions in this chemically pristine material. The transport properties of MATBG as a function of doping are similar to those of high-transition-temperature copper oxides and other unconventional superconductors [1-3], which suggests that MATBG may be a highly interacting system. However, there is no direct experimental evidence of strong many-body correlations in MATBG. In this talk, I will present the unusual spectroscopic characteristics found on MATBG, obtained using a scanning tunneling microscope, and describe how these correlated features allow us to establish a more concrete connection between MATBG and high-Tc cuprates beyond the phenomenological resemblance of their transport phase diagrams [4]. Finally, I will discuss the possibility of symmetry-broken ground states in MATBG and the prospects of probing these states using novel quantum transport and scanning probe techniques.

1.    Cao,Y et al. Nature 556, 80–84 (2018).
2.    Cao,Y et al. Nature 556, 43–50 (2018).
3.    Lee, P. A. et al. Rev. Mod. Phys. 78, 17 (2006).
4.    Xie, Y et al. Nature 572, 101-105 (2019).

Clare Ploucha

Director of Programs

Harvard Quantum Initiative

17 Oxford Street, Jefferson 357

Cambridge, MA 02138

P: 617-495-3388