307 citations · 908 across the 9 of their papers we have counts for
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Single-photon detection enabled by negative differential conductivity in moiré superlattices
Krystian Nowakowski, Hitesh Agarwal, Sergey Slizovskiy +19
Detecting individual light quanta is essential for quantum information, space exploration, advanced machine vision, and fundamental science. Here, we introduce a novel single photo…
Terahertz photocurrent probe of quantum geometry and interactions in magic-angle twisted bilayer graphene
Roshan Krishna Kumar, Geng Li, Riccardo Bertini +24
Moiré materials represent strongly interacting electron systems bridging topological and correlated physics. Despite significant advances, decoding wavefunction properties underlyi…
Cryogenic nano-imaging of second-order moiré superlattices
Niels C. H. Hesp, Sergi Batlle-Porro, Roshan Krishna Kumar +7
Second-order superlattices form when moiré superlattices of similar periodicities interfere with each other, leading to even larger superlattice periodicities. These crystalline st…
Photocurrent as a multi-physics diagnostic of quantum materials
Qiong Ma, Roshan Krishna Kumar, Su-Yang Xu +2
The photoexcitation life-cycle from incident photon (and creation of photoexcited electron hole pair) to ultimate extraction of electrical current is a complex multi-physics proces…
Giant oscillations in a triangular network of one-dimensional states in marginally twisted graphene
S. G. Xu, A. I. Berdyugin, P. Kumaravadivel +12
The electronic properties of graphene superlattices have attracted intense interest that was further stimulated by the recent observation of novel many-body states at "magic" angle…
Excess resistivity in graphene superlattices caused by umklapp electron-electron scattering
J. R. Wallbank, R. Krishna Kumar, M. Holwill +11
Umklapp processes play a fundamental role as the only intrinsic mechanism that allows electrons to transfer momentum to the crystal lattice and, therefore, provide a finite electri…
Measuring Hall Viscosity of Graphene's Electron Fluid
A. I. Berdyugin, S. G. Xu, F. M. D. Pellegrino +10
Materials subjected to a magnetic field exhibit the Hall effect, a phenomenon studied and understood in fine detail. Here we report a qualitative breach of this classical behavior…
High-order fractal states in graphene superlattices
R. Krishna Kumar, A. Mishchenko, X. Chen +7
Graphene superlattices were shown to exhibit high-temperature quantum oscillations due to periodic emergence of delocalized Bloch states in high magnetic fields such that unit frac…
High-temperature quantum oscillations caused by recurring Bloch states in graphene superlattices
R. Krishna Kumar, X. Chen, G. H. Auton +13
Cyclotron motion of charge carriers in metals and semiconductors leads to Landau quantization and magneto-oscillatory behavior in their properties. Cryogenic temperatures are usual…