Ali’s collaborative work with the Malis group on optical properties of AlInN in published in Applied Physics Letters
March 21, 2016 Ali’s collaborative work with the Malis group on optical properties of AlInN in published in Applied Physics Letters.
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Saeed and Geoff contribute to work on noise suppression in spin qubits
March 18, 2016 Saeed and Geoff contribute to work on noise suppression in spin qubits. Read more. Image courtesy of Ferdinand Kuemmeth.
Geoff’s and Saeed’s paper on advances in MBE growth of ultrahigh mobility GaAs is published
February 26, 2016 Geoff’s and Saeed’s paper on advances in MBE growth of ultrahigh mobility GaAs is published. Congratulations to Geoff and Saeed.
Prof. Manfra receives Seeds of Success Award from Purdue University
November 30, 2015 Prof. Manfra receives Seeds of Success Award from Purdue University. This award recognizes research funding awards in excess of $1 million.
Material grown by Manfra Group allows observation phase transition thought impossible
October 26, 2015 Material grown by Manfra Group allows observation phase transition thought impossible. Read more.
Material grown by Manfra Group used to fabricate artificial graphene and featured as JVST Editors Pick
October 15, 2015 Material grown by Manfra Group used to fabricate artificial graphene and featured as JVST Editors Pick. Read more.
Prof. Manfra named APS Fellow
October 5, 2015 Prof. Manfra named APS Fellow for advancing MBE growth of AlGaAs/GaAs and AlGaN/GaN heterostructures that enable fundamental understanding of 2D electron correlation effects and realization of novel devices.
Non-Abelian Phases in the Fractional Quantum Hall Regime
The fractional quantum Hall effect (FQHE) occurs in a two-dimensional electron gas (2DEG) subjected to a perpendicular magnetic field at low temperature. It is now understood to arise from strong electron-electron interactions. In transport experiments the FHQE is characterized by Hall resistance quantized to rational fractional values of h/e2 and vanishingly small longitudinal resistance. Quasi-particle excitations in the FQHE are called anyons.
Engineering Heterostructures for High Fidelity Spin Qubits
Nanostructures such quantum dots fabricated on modulation-doped AlGaAs/GaAs heterostructures are widely used in spin-based approaches to quantum computing. Charge noise in these devices, however, limits gate fidelity. A quiet electrostatic environment is therefore essential for further progress.
Ultra-High Mobility 2DEGs and 2DHSs in GaAs Grown by Molecular Beam Epitaxy
A major thrust in the Quantum Semiconductor Systems group is growth of extremely high quality GaAs/AlGaAs heterostructures. One metric of quality is 2D mobility, which can now exceed 30 x 106 cm2/Vs at low temperatures. At low temperature mobility is limited by imperfections in the grown sample. Imperfections include intentionally introduced charged impurities, unintentional background charged impurities and structural defects.
Our efforts are focused in 3 areas: improved MBE vacuum conditions, source material purity, and heterostructure design.