Presentation Title

Mott Insulator to Superfluid Quantum Phase Transition for Helium on Strained Graphene

Presenter's Name(s)

Jiangyong YuFollow

Project Collaborators

Nathan Nichols, Taras I. Lakoba, Valeri Kotov, Adrian Del Maestro

Abstract

An exciting development in the field of correlated systems is the possibility of realizing two-dimensional (2D) superfluidity, particularly by adsorbing helium on novel 2D quantum materials, such as graphene. How superfluidity emerges in this system, and whether it could exist in the first, second, etc. layer, has been a topic of considerable controversy. We argue theoretically that under certain favorable external conditions where uniaxial stress is applied to graphene, 2D anisotropic superfluidity can form in the first layer. This result is based on preliminary large-scale ab initio quantum Monte Carlo simulations combined with a mapping of the problem to an effective Bose-Hubbard model. We show that a critical ratio of the onsite repulsion to hopping strength (U/t) can be achieved via strain, allowing for a quantum phase transition to a superfluid state below a critical value. Our analysis supports, for the first time, the existence of an unconventional first layer 2D anisotropic superfluid, possibly also exhibiting supersolid correlations reflecting the underlying graphene lattice structure.

Primary Faculty Mentor Name

Adrian Del Maestro

Secondary Mentor NetID

tlakoba, vkotov

Secondary Mentor Name

Taras Lakoba, Valeri Kotov

Status

Graduate

Student College

College of Arts and Sciences

Program/Major

Physics

Primary Research Category

Engineering & Physical Sciences

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Mott Insulator to Superfluid Quantum Phase Transition for Helium on Strained Graphene

An exciting development in the field of correlated systems is the possibility of realizing two-dimensional (2D) superfluidity, particularly by adsorbing helium on novel 2D quantum materials, such as graphene. How superfluidity emerges in this system, and whether it could exist in the first, second, etc. layer, has been a topic of considerable controversy. We argue theoretically that under certain favorable external conditions where uniaxial stress is applied to graphene, 2D anisotropic superfluidity can form in the first layer. This result is based on preliminary large-scale ab initio quantum Monte Carlo simulations combined with a mapping of the problem to an effective Bose-Hubbard model. We show that a critical ratio of the onsite repulsion to hopping strength (U/t) can be achieved via strain, allowing for a quantum phase transition to a superfluid state below a critical value. Our analysis supports, for the first time, the existence of an unconventional first layer 2D anisotropic superfluid, possibly also exhibiting supersolid correlations reflecting the underlying graphene lattice structure.