75 citations · 190 across the 10 of their papers we have counts for
10 papers
Optical Cooling of Dot-in-crystal Halide Perovskites: Challenges of Nonlinear Exciton Recombination
Yasuhiro Yamada, Takeru Oki, Takeshi Morita +5
Highly efficient anti-Stokes (AS) photoluminescence (PL) is observed from halide perovskite quantum dots (QDs) due to their strong electron-phonon interactions. The AS PL is partic…
Anti-Stokes Photoluminescence from CsPbBr3 Nanostructures Embedded in a CsPbBr Crystal
Yuto Kajino, Shuji Otake, Takumi Yamada +6
Lead halide perovskites possess high photoluminescence (PL) efficiency and strong electron-phonon interactions, and therefore the optical cooling using up-conversion PL has been ex…
Quantized exciton-exciton annihilation in monolayer WS2 on SrTiO3 substrates with atomically flat terraces
Yuto Kajino, Kohei Sakanashi, Nobuyuki Aoki +4
Monolayer materials are strongly affected by their potential fluctuations, which are induced by an intrinsic corrugation or the surface roughness of the substrate. We compare the e…
Polaron Masses in CH3NH3PbX3 Perovskites Determined by Landau Level Spectroscopy in Low Magnetic Fields
Yasuhiro Yamada, Hirofumi Mino, Takuya Kawahara +3
We investigate the electron-phonon coupling in CH3NH3PbX3 lead halide perovskites through the observation of Landau levels and high-order excitons at weak magnetic fields, where th…
Exciton Lifetime Paradoxically Enhanced by Dissipation and Decoherence - Toward Efficient Energy Conversion of Solar Cell
Yasuhiro Yamada, Youhei Yamaji, Masatoshi Imada
Energy dissipation and decoherence are at first glance harmful to acquiring long exciton lifetime desired for efficient photovoltaics. In the presence of both optically forbidden (…
Universal departure from Johnson-Nyquist relation caused by limited resolution
Yasuhiro Yamada, Masatoshi Imada
Exploiting the two-point measurement statistics, we propose a quantum measurement scheme of current with limited resolution of electron counting. Our scheme is equivalent to the fu…
Interplay of Kondo and superconducting correlations in the nonequilibrium Andreev transport through a quantum dot
Yasuhiro Yamada, Yoichi Tanaka, Norio Kawakami
Using the modified perturbation theory, we theoretically study the nonequilibrium Andreev transport through a quantum dot coupled to normal and superconducting leads (N-QD-S), whic…
Enhanced Andreev Tunneling via the Kondo Resonance in a Quantum Dot at Finite Bias
Yasuhiro Yamada, Yoichi Tanaka, Norio Kawakami
We study the nonequilibrium transport through a quantum dot coupled to normal and superconducting leads. We use the modified second-order perturbation theory to calculate the diffe…
X-ray Anomalous Scattering of Diluted Magnetic Oxide Semiconductors: Possible Evidence of Lattice Deformation for High Temperature Ferromagnetism
Takeshi Matsumura, Daisuke Okuyama, Shinya Niioka +7
We have examined whether the Co ions crystallographically substitute on the Ti sites in rutile and anatase Ti_{1-x}_{x}_{2-delta}$ thin films that exhibit room-temperature f…
Magneto-Optical Spectroscopy of Anatase TiO2 Doped with Co
T. Fukumura, Y. Yamada, K. Tamura +10
Magneto-optical spectroscopy of a transparent ferromagnetic semiconductor, anatase TiO2 doped with Co, is carried out at room temperature. A large magneto-optical response with fer…