Presentation Title
Mott Insulator to Superfluid Quantum Phase Transition for Helium on Strained Graphene
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 Name
Taras Lakoba, Valeri Kotov
Faculty/Staff Collaborators
Nathan Nichols, Taras I. Lakoba, Valeri Kotov, Adrian Del Maestro
Status
Graduate
Student College
College of Arts and Sciences
Program/Major
Physics
Primary Research Category
Engineering & Physical Sciences
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.