870 citations · 2.5k across the 23 of their papers we have counts for
23 papers
Noise probing of topological band gaps in dispersionless quantum states
Alexander Kruchkov, Shinsei Ryu
We uncover a useful connection between the integrated current noise and the topological band gap in dispersionless quantum states, $\int d ω[ \mathcal S^{\text{flat}}_{xx} +…
Unconventional superfluidity and quantum geometry of topological bosons
Ilya Lukin, Andrii Sotnikov, Alexander Kruchkov
We investigate superfluidity of bosons in gapped topological bands and discover a new phase that has no counterparts in the previous literature. This phase is characterized by a hi…
Anomalous conductivity of -symmetric Fermi liquids
Alexander Kruchkov
We consider a non-Hermitian yet -symmetric Fermi liquid (-FL) in external electric fields. Due to -symmetry, the system exhibits real spec…
Quantum transport in dispersionless electronic bands
Alexander Kruchkov
Flat electronic bands are counterintuitive: with the electron velocity vanishing, our conventional notions of quasiparticle transport are no longer valid. We here study the quantum…
Engineering SYK interactions in disordered graphene flakes under realistic experimental conditions
Marta Brzezinska, Yifei Guan, Oleg V. Yazyev +2
We model SYK (Sachdev-Ye-Kitaev) interactions in disordered graphene flakes up to 300 000 atoms (100 nm in diameter) subjected to an out-of-plane magnetic field of 5-20 T…
Re-entrant magic-angle phenomena in twisted bilayer graphene in integer magnetic fluxes
Yifei Guan, Oleg V. Yazyev, Alexander Kruchkov
In this work we address the re-entrance of magic-angle phenomena (band flatness and quantum-geometric transport) in twisted bilayer graphene (TBG) subjected to strong magnetic flux…
Unconventional Flat Chern Bands and 2 Charges in Skyrmionic Moiré Superlattices
Yifei Guan, Oleg V. Yazyev, Alexander Kruchkov
The interplay of topological characteristics in real space and reciprocal space can lead to the emergence of unconventional topological phases. In this Letter, we implement a novel…
Origin of band flatness and constraints of higher Chern numbers
Alexander Kruchkov
Flat bands provide a natural platform for emergent electronic states beyond Landau paradigm. Among those of particular importance are flat Chern bands, including bands of higher Ch…
Moiré Flat Bands in Twisted Double Bilayer Graphene
Fatemeh Haddadi, QuanSheng Wu, Alex J. Kruchkov +1
We investigate twisted double bilayer graphene (TDBG), a four-layer system composed of two AB-stacked graphene bilayers rotated with respect to each other by a small angle. Our ab…
Non-Hermitian Boundary Modes
Dan S. Borgnia, Alex Jura Kruchkov, Robert-Jan Slager
We consider conditions for the existence of boundary modes in non-Hermitian systems with edges of arbitrary co-dimension. Through a universal formulation of formation criteria for…
Magic Angle Hierarchy in Twisted Graphene Multilayers
Eslam Khalaf, Alex J. Kruchkov, Grigory Tarnopolsky +1
When two monolayers of graphene are stacked with a small relative twist angle, the resulting band structure exhibits a remarkably flat pair of bands at a sequence of 'magic angles'…
Origin of Magic Angles in Twisted Bilayer Graphene
Grigory Tarnopolsky, Alex J. Kruchkov, Ashvin Vishwanath
Twisted Bilayer graphene (TBG) is known to feature isolated and relatively flat bands near charge neutrality, when tuned to special magic angles. However, different criteria for th…
Electric field-driven topological phase switching and skyrmion lattice metastability in magnetoelectric CuOSeO
J. S. White, I. Živković, A. J. Kruchkov +3
Due to their topological protection and nanometric size, magnetic skyrmions are anticipated to form components of new high-density memory technologies. In metallic systems skyrmion…
In situ Electric Field Skyrmion Creation in Magnetoelectric CuOSeO
Ping Huang, Marco Cantoni, Alex Kruchkov +4
Magnetic skyrmions are localized nanometric spin textures with quantized winding numbers as the topological invariant. Rapidly increasing attention has been paid to the investigati…
Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscopy
G. Berruto, I. Madan, Y. Murooka +11
We demonstrate that light-induced heat pulses of different duration and energy can write skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination…
Direct control of the skyrmion phase stability by electric field in a magnetoelectric insulator
Alex J. Kruchkov, J. S. White, M. Bartowiak +3
Magnetic skyrmions are topologically protected spin-whirl quasiparticles currently considered as promising components for ultra-dense memory devices. In the bulk they form lattices…
Skyrmion Lattices in Electric Fields
Alex J. Kruchkov, Henrik M. Rønnow
This paper studies the influence of electric fields on the skyrmion lattice (SkL) in insulating skyrmion compounds with weak magnetoelectric (ME) coupling. The ME coupling mechanis…
One-dimensional Bose-Einstein condensation of photons in a microtube
Alex J. Kruchkov
This paper introduces a quasiequilibrium one-dimensional Bose-Einstein condensation of photons trapped in a microtube. Light modes with a cut-off frequency (a photon's "mass") inte…
Dramatic pressure-driven enhancement of bulk skyrmion stability
I. Levatić, P. Popčević, V. Šurija +6
The recent discovery of magnetic skyrmion lattices initiated a surge of interest in the scientific community. Several novel phenomena have been shown to emerge from the interaction…
Radiation spectrum of systems with condensed light
Alex Kruchkov
Experimental observation of Bose-Einstein condensation (BEC) of photons inside a microcavity induced an extensive study of the phenomenon. Beyond the purely theoretical interest, t…
Bose-Einstein condensation of light in a cavity
Alex Kruchkov
The paper considers Bose-Einstein condensation (BEC) of light in a cavity with medium. In the framework of two-level model we show the effect of gaseous medium on the critical temp…
Bose-Einstein condensation of photons in an ideal atomic gas
Alex Kruchkov, Yurii Slyusarenko
We study peculiarities of Bose-Einstein condensation of photons that are in thermodynamic equilibrium with atoms of noninteracting gases. General equations of the thermodynamic equ…
Mechanism of collisionless sound damping in dilute Bose gas with condensate
Yu. Slyusarenko, A. Kruchkov
We develop a microscopic theory of sound damping due to Landau mechanism in dilute gas with Bose condensate. It is based on the coupled evolution equations of the parameters descri…