# Quantum Phase Transitions in Graphene Coupled to a Twisted WSe2 Moiré Ferroelectricity

## TL;DR

Researchers used twisted WSe2 to break graphene's symmetry, enabling room-temperature quantum phase transitions and new electronic behaviors.

## Contribution

Moiré ferroelectricity in t-WSe2 enables room-temperature metal-insulator transitions and tunable quantum phases in graphene.

## Key findings

- Moiré ferroelectricity in t-WSe2 breaks graphene's sublattice symmetry, inducing a room-temperature metal-insulator transition.
- Graphene exhibits Fermi-liquid and non-Fermi-liquid metallic phases under electrostatic doping.
- Finite-size scaling analysis confirms continuous quantum phase transitions at ambient conditions.

## Abstract

Sublattice symmetry in graphene governs its Dirac semimetal behavior, where electrons exhibit linear dispersion, limiting its potential for technological applications. Here, moiré ferroelectricity in twisted WSe2 (t‐WSe2) is exploited to break graphene's sublattice symmetry, inducing a metal‐to‐insulator transition (MIT) near room temperature. The periodic polarization domains in t‐WSe2 imprint an electrostatic potential onto graphene, breaking its sublattice symmetry and leading to the emergence of a local Dirac point, as observed in the transfer characteristics of a t‐WSe2/graphene field‐effect transistor. Temperature‐dependent transport measurements reveal multiple MIT points at relatively high temperatures, attributed to the room‐temperature ferroelectric polarization in t‐WSe2. Furthermore, A distinct metallic phases is identified exhibiting T
2 and linear‐T dependent longitudinal resistance under electrostatic doping, indicative of Fermi‐liquid and non‐Fermi‐liquid metallic behavior, respectively. Finally, finite‐size scaling analysis of R
xx near the MIT points indicates continuous quantum phase transitions near room temperature, establishing moiré ferroelectricity as a pathway for engineering quantum electronic phases of monolayer graphene at ambient conditions.

Moiré ferroelectricity in twisted WSe2 (t‐WSe2) breaks graphene's sublattice symmetry, inducing a room‐temperature metal‐insulator transition. Coupling graphene with ferroelectric domains of t‐WSe2 creates local Dirac points and metallic phases with Fermi‐liquid and non‐Fermi‐liquid behavior. Scaling analysis confirms continuous quantum phase transitions, establishing a route totunable quantum phases in graphene at ambient conditions.