Moiré nematic phase in twisted double bilayer graphene

Journal Article · Thu Dec 23 00:00:00 EST 2021 · Nature Physics

DOI:https://doi.org/10.1038/s41567-021-01438-2· OSTI ID:1961319

Rubio-Verdú, Carmen ^[1]; Turkel, Simon ^[2]; Song, Yuan ^[2]; Klebl, Lennart ^[3]; Samajdar, Rhine ^[4]; Scheurer, Mathias S. ^[5]; Venderbos, Jörn W. F. ^[6]; Watanabe, Kenji ^[7]; Taniguchi, Takashi ^[7]; Ochoa, Héctor ^[2]; Xian, Lede ^[8]; Kennes, Dante M. ^[9]; Fernandes, Rafael M. ^[10]; Rubio, Ángel ^[11]; Pasupathy, Abhay N. ^[2]

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1. Columbia Univ., New York, NY (United States); University of Minnesota
2. Columbia Univ., New York, NY (United States)
3. RWTH Aachen Univ., and JARA Fundamentals of Future Information Technology (Germany)
4. Harvard Univ., Cambridge, MA (United States)
5. Harvard Univ., Cambridge, MA (United States); Univ. of Innsbruck (Austria)
6. Drexel Univ., Philadelphia, PA (United States)
7. National Inst. for Materials Science, Tsukuba (Japan)
8. Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Songshan Lake Materials Laboratory, Guangdong (China)
9. RWTH Aachen Univ., and JARA Fundamentals of Future Information Technology (Germany); Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany)
10. Univ. of Minnesota, Minneapolis, MN (United States)
11. Max Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Flatiron Inst., New York, NY (United States); UPV/EHU, Donostia (Spain)

Graphene moiré superlattices display electronic flat bands. At integer fillings of these flat bands, energy gaps due to strong electron-electron interactions are generally observed. However, the presence of other correlation-driven phases in twisted graphitic systems at non-integer fillings is unclear. Here, we report the existence of threefold rotational symmetry breaking in twisted double bilayer graphene. Using spectroscopic imaging over large and uniform areas to characterize the direction and degree of C₃ symmetry breaking, we find it to be prominent only at energies corresponding to the flat bands and nearly absent in the remote bands. We demonstrate that the magnitude of the rotational symmetry breaking does not depend on the degree of the heterostrain or the displacement field, being instead a manifestation of an interaction-driven electronic nematic phase. We show that the nematic phase is a primary order that arises from the normal metal state over a wide range of doping away from charge. Furthermore, our modelling suggests that the nematic instability is not associated with the local scale of the graphene lattice, but is an emergent phenomenon at the scale of the moiré lattice.

• Research Organization: Univ. of Minnesota, Minneapolis, MN (United States)
• Sponsoring Organization: Air Force Office of Scientific Research; CREST; JSPS KAKENHI; MEXT; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020045
• OSTI ID: 1961319
• Journal Information: Nature Physics, Journal Name: Nature Physics Journal Issue: 2 Vol. 18; ISSN 1745-2473
• Publisher: Nature Publishing Group (NPG)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Electronic properties and materials
Quantum fluids and solids