7 citations · 15 across the 14 of their papers we have counts for
16 papers
Up/down-conversion of infrared light by few-layer graphene polytypes
Patrick Johansen Sarsfield, Takaaki V. Joya, Takuto Kawakami +2
Optical nonlinearity of materials with broken inversion symmetry enables two-photon processes where an incoming pair of photons can generate an up-converted photon with the combine…
Second-harmonic generation in twisted double bilayer graphene: Double-resonant enhancement from moiré flat bands
Takaaki V. Joya, Takuto Kawakami, Mikito Koshino
We theoretically investigate second-harmonic generation (SHG) in twisted double bilayer graphene (TDBG) with AB--AB and AB--BA stacking configurations using a perturbative approach…
Twist-configured moire-moire reconstruction governs diverse commensurate double-moire phases in twisted bilayer graphene on h-BN
Yuta Seo, Naoto Nakatsuji, Jimpei Kawase +6
The coexistence of multiple moire lattices in van der Waals heterostructures raises a fundamental question: how do distinct moire patterns interact and reconstruct? Here, we invest…
Landau levels and magneto-optics in 30 quasi-periodic twisted bilayer graphene
Masaru Hitomi, Takuto Kawakami, Mikito Koshino
We develop a theoretical framework for Landau levels in quasi-periodic twisted bilayer graphene at a twist angle, a system without translational symmetry but possessing…
Quantum higher-spin Hall insulators
Takuto Kawakami, Igor Kuzmenko, Yshai Avishai +2
We develop a theory of quantum spin Hall insulators with arbitrary spin . Our analysis demonstrates that such systems support pairs of helical edge modes protec…
One-Dimensional Electronic States in a Moiré Superlattice of Twisted Bilayer WTe2
Takuto Kawakami, Hayato Tateish, Daiki Yoshida +10
One-dimensional (1D) moiré superlattices provide a new route to engineering reduced-dimensional electronic states in van der Waals materials, yet their electronic structure and mic…
Ferroelectricity in a magnon Bose-Einstein condensate: Nonreciprocal superfluidity, exceptional points, and Majorana bosons
Kazuki Yamamoto, Takuto Kawakami, Mikito Koshino
We investigate a ferroelectric instability of a magnon Bose-Einstein condensate, mediated by its interaction with an electric field through a geometric Aharonov-Casher (AC) phase.…
One-dimensional moiré engineering in zigzag graphene nanoribbons on hBN
Ryosuke Okumura, Naoto Nakatsuji, Takuto Kawakami +1
We study the structural relaxation and electronic properties of a one-dimensional (1D) moiré system composed of a zigzag graphene nanoribbon (GNR) placed on a hexagonal boron nitri…
Resonant Structure of Second Harmonic Generation in Multilayer Graphene Polytypes
Patrick Johansen Sarsfield, Takaaki V. Joya, Takuto Kawakami +2
Second harmonic generation (SHG) is a powerful optical tool for identifying non-centrosymmetric crystalline structures. Here, we analyze SHG in multilayer graphenes (MLG), with a f…
Twist-angle tunable Josephson junctions in three-dimensional superconductors
Tenta Tani, Takuto Kawakami, Mikito Koshino
We theoretically investigate the superconducting phase and perpendicular Josephson supercurrent in twisted three-dimensional (3D) superconductors, where two layered 3D materials ar…
Non-Abelian Chern band in rhombohedral graphene multilayers
Taketo Uchida, Takuto Kawakami, Mikito Koshino
Moiré flat bands in rhombohedral multilayer graphene provide a platform for exploring interaction-driven topological phases, where a single isolated band often forms a Chern band.…
Singular flat bands in three dimensions: Landau level spreading, quantum geometry, and Weyl reconstruction
Takuto Kawakami, Yuji Igarashi, Mikito Koshino
We theoretically investigate three-dimensional singular flat band systems, focusing on their quantum geometric properties and response to external magnetic fields. As a representat…
Moiré Band Engineering in Twisted Trilayer WSe2
Naoto Nakatsuji, Takuto Kawakami, Hayato Tateishi +2
We present a systematic theoretical study on the structural and electronic properties of twisted trilayer transition metal dichalcogenide (TMD) WSe, where two independent moiré…
Shift current response in twisted double bilayer graphenes
Takaaki V. Joya, Takuto Kawakami, Mikito Koshino
We calculate the shift current response in twisted double bilayer graphenes (TDBG) by applying the perturbative approach to the effective continuum Hamiltonian. We have performed a…
Electromagnetic response in dipole superfluids: vortex lattices and singular domain walls
Kazuki Yamamoto, Takuto Kawakami, Mikito Koshino
Among the most significant macroscopic quantum phenomena in condensed matter physics is the Meissner effect observed in superconductivity, which arises from the unique interaction…
Low-temperature thermal transport in moiré superlattices
Lukas P. A. Krisna, Takuto Kawakami, Mikito Koshino
We calculate the phonon thermal conductivity of various moiré bilayer systems using a continuum approach and the semiclassical transport theory. When the twist angle is close to 0,…