# Tuning superconductivity in twisted bilayer graphene

**Authors:** Matthew Yankowitz, Shaowen Chen, Hryhoriy Polshyn, K. Watanabe, T. Taniguchi, David Graf, Andrea F. Young, Cory R. Dean  
**arXiv:** [1808.07865](https://arxiv.org/abs/1808.07865)  
**Date:** 2018-08-23  
**Summary page:** https://www.summarizepaper.com/en/paper/1808.07865v1/

## Key points

- Study focused on twisted bilayer graphene (tBLG) with a twist angle close to 1.1$^{\circ}
- Formation of isolated flat band with strong electron correlations at low carrier density
- Manipulation of states by controlling interlayer electrical bias and electronic coupling
- Successful induction of superconductivity in tBLG device with twist angle larger than 1.1$^{\circ} using hydrostatic pressure
- Low disorder levels in devices allow for detailed exploration of superconducting phase diagram and its relationship to nearby insulating phases
- Twisted bilayer graphene identified as a flexible platform for investigating novel correlated states in condensed matter physics

## Summary

A recent study by Matthew Yankowitz, Shaowen Chen, Hryhoriy Polshyn, K. Watanabe, T. Taniguchi, David Graf, Andrea F. Young and Cory R. Dean has explored the emergence of superconducting and correlating insulating states in twisted bilayer graphene (tBLG) with a twist angle very close to 1.1$^{\circ}$. This specific twist angle leads to the formation of an isolated flat band where strong electron correlations dominate at low carrier density. The researchers have demonstrated that these unique states can be manipulated by controlling various degrees of freedom within the system including interlayer electrical bias and interlayer electronic coupling. Notably, they have successfully induced superconductivity in a device with a twist angle larger than 1.1$^{\circ}$ - where correlated phases are typically absent - by varying the interlayer spacing using hydrostatic pressure. Furthermore, the devices used in this study exhibit very low levels of disorder which allows for a detailed exploration of the superconducting phase diagram and its relationship to nearby insulating phases. These findings highlight twisted bilayer graphene as an exceptionally flexible platform for investigating novel correlated states in condensed matter physics. This comprehensive research sheds light on the intricate interplay between electron correlations and superconductivity in tBLG systems with different twist angles, offering valuable insights into potential applications of these materials in future technological advancements.