539 citations · 2.6k across the 30 of their papers we have counts for
28 papers · 1 filter
Spontaneous time-reversal symmetry breaking in twisted double bilayer graphene
Manabendra Kuiri, Christopher Coleman, Zhenxiang Gao +6
Twisted double bilayer graphene (tDBG) comprises two Bernal-stacked bilayer graphene sheets with a twist between them. Gate voltages applied to top and back gates of a tDBG device…
A robust protocol for entropy measurement in mesoscopic circuits
Tim Child, Owen Sheekey, Silvia Lüscher +4
Previous measurements utilizing Maxwell relations to measure change in entropy, , demonstrated remarkable accuracy of measuring the spin-1/2 entropy of electrons in a weakly cou…
Differential thermopower images as a probe of many-body effects in quantum point contacts
Yuan Ren, Joshua Folk, Yigal Meir +2
Mesoscopic circuit elements such as quantum dots and quantum point contacts (QPCs) offer a uniquely controllable platform for engineering complex quantum devices, whose tunability…
Entropy measurement of a strongly coupled quantum dot
Tim Child, Owen Sheekey, Silvia Lüscher +8
The spin 1/2 entropy of electrons trapped in a quantum dot has previously been measured with great accuracy, but the protocol used for that measurement is valid only within a restr…
Activation of magnetic moments in CVD-grown graphene by annealing
Hyungki Shin, Ebrahim Sajadi, Ali Khademi +2
Effects of annealing on chemical vapor deposited graphene are investigated via a weak localization magnetoresistance measurement. Annealing at \SI{300}{\celsius} in inert gases, a…
Weak localization measurements of electronic scattering rates in Li-doped epitaxial graphene
Ali Khademi, Kristen Kaasbjerg, Pinder Dosanjh +4
Early experiments on alkali-doped graphene demonstrated that the dopant adatoms modify the conductivity of graphene significantly, as extra carriers enhance conductivity while Coul…
Detecting the universal fractional entropy of Majorana zero modes
Eran Sela, Yuval Oreg, Stephan Plugge +3
A pair of Majorana zero modes (MZMs) constitutes a nonlocal qubit whose entropy is . Upon strongly coupling one of the constituent MZMs to a reservoir with a continuous den…
Direct Entropy Measurement in a Mesoscopic Quantum System
Nikolaus Hartman, Christian Olsen, Silvia Lüscher +5
The entropy of an electronic system offers important insights into the nature of its quantum mechanical ground state. This is particularly valuable in cases where the state is diff…
Gate-induced superconductivity in a monolayer topological insulator
Ebrahim Sajadi, Tauno Palomaki, Zaiyao Fei +7
The layered semimetal WTe_2 has recently been found to be a two-dimensional topological insulator (2D TI) when thinned down to a single monolayer, with conducting helical edge chan…
Quantum Lifetime in Ultra-High Quality GaAs Quantum Wells: Relationship to and Impact of Density Fluctuations
Qi Qian, James R. Nakamura, Saeed Fallahi +6
We consider quantum lifetime derived from low-field Shubnikov-de Haas oscillations as a metric of quality of the two-dimensional electron gas in GaAs quantum wells that expresses l…
Alkali doping of graphene: the crucial role of high temperature annealing
Ali Khademi, Ebrahim Sajadi, Pinder Dosanjh +5
The doping efficiency of lithium deposited at cryogenic temperatures on epitaxial and CVD monolayer graphene has been investigated under ultra-high vacuum conditions. Change of cha…
Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure
M. Kjaergaard, F. Nichele, H. J. Suominen +8
The prospect of coupling a two-dimensional (2D) semiconductor heterostructure to a superconductor opens new research and technology opportunities, including fundamental problems in…
Milestones toward Majorana-based quantum computing
David Aasen, Michael Hell, Ryan V. Mishmash +8
We introduce a scheme for preparation, manipulation, and readout of Majorana zero modes in semiconducting wires with mesoscopic superconducting islands. Our approach synthesizes re…
Edge Transport in the Trivial Phase of InAs/GaSb
Fabrizio Nichele, Henri J. Suominen, Morten Kjaergaard +16
We present transport and scanning SQUID measurements on InAs/GaSb double quantum wells, a system predicted to be a two-dimensional topological insulator. Top and back gates allow i…
Influence of impurity spin dynamics on quantum transport in epitaxial graphene
Samuel Lara-Avila, Sergey Kubatkin, Oleksiy Kashuba +6
Experimental evidence from both spin-valve and quantum transport measurements points towards unexpectedly fast spin relaxation in graphene. We report magnetotransport studies of ep…
Bias-induced breakdown of electron solids in the second Landau level
Alexander V. Rossokhaty, Silvia Lüscher, Joshua A. Folk +3
Reentrant integer quantum Hall (RIQH) states are believed to be correlated electron solid phases, though their microscopic description remains unclear. As bias current increases, l…
Low-temperature illumination and annealing of ultra-high quality quantum wells
Mohammad Samani, Alexander V. Rossokhaty, Ebrahim Sajadi +5
The effects of low temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below…
Origins of Nonlocality near the Dirac Point in Graphene
Julien Renard, Matthias Studer, Joshua A. Folk
We present an experimental study of nonlocal electrical signals near the Dirac point in graphene. The in-plane magnetic field dependence of the nonlocal signal confirms the role of…
Gate voltage control over spin relaxation length
S. M. Frolov, W. W. Yu, S. Luescher +2
Spin currents in channels of a high mobility GaAs/AlGaAs two-dimensional electron gas are generated and detected using spin-polarized quantum point contacts. We have recently shown…
Measurement of spin-dependent conductivities in a two-dimensional electron gas
H. Ebrahimnejad, Y. Ren, S. M. Frolov +3
Spin accumulation is generated by injecting an unpolarized charge current into a channel of GaAs two-dimensional electron gas subject to an in-plane magnetic field, then measured i…
Numerical study of resonant spin relaxation in quasi-1D channels
S. Luescher, S. M. Frolov, J. A. Folk
Recent experiments demonstrate that a ballistic version of spin resonance, mediated by spin-orbit interaction, can be induced in narrow channels of a high-mobility GaAs two-dimensi…
Rippled Graphene in an In-Plane Magnetic Field: Effects of a Random Vector Potential
Mark B. Lundeberg, Joshua A. Folk
We report measurements of the effects of a random vector potential generated by applying an in-plane magnetic field to a graphene flake. Magnetic flux through the ripples cause orb…
Spin-resolved Quantum Interference in Graphene
Mark B. Lundeberg, Joshua A. Folk
The unusual electronic properties of single-layer graphene make it a promising material system for fundamental advances in physics, and an attractive platform for new device techno…
Electrical generation of pure spin currents in a two-dimensional electron gas
S. M. Frolov, A. Venkatesan, W. Yu +2
Pure spin currents are measured in micron-wide channels of GaAs two-dimensional electron gas (2DEG). Spins are injected and detected using quantum point contacts, which become spin…