T
Takaaki Koga
Researcher at Hokkaido University
Publications - 68
Citations - 2990
Takaaki Koga is an academic researcher from Hokkaido University. The author has contributed to research in topics: Rashba effect & Quantum well. The author has an hindex of 21, co-authored 68 publications receiving 2812 citations. Previous affiliations of Takaaki Koga include National Presto Industries & Nippon Telegraph and Telephone.
Papers
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Spin-filter device based on the Rashba effect using a nonmagnetic resonant tunneling diode.
TL;DR: Detailed calculations using the InAlAs/InGaAs material system reveal that a splitting of a peak should be observed in the I-V curve of this device as a result of the spin-filtering effect.
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Rashba spin-orbit coupling probed by the weak antilocalization analysis in InAlAs/InGaAs/InAlAs quantum wells as a function of quantum well asymmetry.
TL;DR: In this paper, the authors investigated the values of the Rashba spin-orbit coupling constant alpha in In(0.52)Al (0.48)As/In( 0.53)Ga(0.,0.47)In(0,0.51)Al(0,.48)InIn(In,0,1.52),Al( 0,0.,1.48),In, 0,1.,0,2.
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Low-dimensional thermoelectric materials
Mildred S. Dresselhaus,Gene Dresselhaus,X. Sun,Zhuomin M. Zhang,Stephen B. Cronin,Takaaki Koga +5 more
TL;DR: In this article, the potential of low dimensional thermoelectric materials for enhanced performance is reviewed, with particular attention given to quantum wells and quantum wires, and the high potential of bismuth as a low-dimensional material is discussed.
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Thermal conductivity of symmetrically strained Si/Ge superlattices
Theodorian Borca-Tasciuc,Weili Liu,Jianlin Liu,Taofang Zeng,D. W. Song,C. D. Moore,Gang Chen,Kang L. Wang,Mark S. Goorsky,Tamara Radetić,Ronald Gronsky,Takaaki Koga,Mildred S. Dresselhaus +12 more
TL;DR: In this paper, temperature-dependent thermal conductivity measurements in the crossplane direction of symmetrically strained Si/Ge superlattices are reported, and the effect of doping, period thickness and dislocations on the thermal conductivities reduction of the Si/G super lattices is investigated.
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Experimental proof-of-principle investigation of enhanced Z3DT in (001) oriented Si/Ge superlattices
TL;DR: In this article, an experimental proof-of-principle of an enhanced Z3DT (thermoelectric figure of merit) is demonstrated using (001) oriented Si/Ge superlattices.