著者

Lee J. D. Gomi H. Hase Muneaki

出版者

American Institute of Physics

雑誌

Journal of applied physics (ISSN:00218979)

巻号頁・発行日

vol.106, no.8, pp.083501, 2009-10-16

被引用文献数

1 3

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Using the nonperturbative many-body time-dependent approach, we investigate the nonequilibrium dynamics of the coherent longitudinal optical phonon-plasmon coupled (LOPC) modes in a polar semiconductor and explore their coherent optical control and eventually the carrier mobility of the semiconductor. The basic idea for a control of the carrier mobility is to manipulate the ultrafast dephasing of the coherent carrier-relevant LOPC mode. We theoretically propose two possible options to realize the idea and reach the final goal. One is to optimize a semiconductor by finely balancing two kinds of carrier densities by chemical doping and optical doping (or photodoping), where the relaxation of the coherent carrier-relevant LOPC mode would respond in a (weak) singular way. It is found that, in this way, the carrier mobility could be enhanced by a few tens of percent. The other is to optimize the optical pumping laser. In this option, the pulse train creating pure virtual carriers through the below-band-gap excitation would be incorporated for an optical pumping, which can make possible the dephasing-free dynamics of the coherent carrier-relevant LOPC mode. The carrier mobility can then be efficiently controlled and dramatically enhanced by synchronizing the pulse train with its coherent oscillation. This might imply one of ultimate ways to control the carrier mobility of the semiconductor

著者

Lee J. D. Nagatomi T. (Translator) Mizutani G. (Translator) Endo K. (Translation Supervisor)

出版者

Surface Analysis Society of Japan

雑誌

Journal of Surface Analysis (ISSN:13411756)

巻号頁・発行日

vol.17, no.2, pp.64-86, 2010-12

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The angle-resolved photoemission spectroscopy (ARPES) is a powerful experimental tool to probe themomentum-resolved electronic structure, i.e., the electronic band dispersion ε(k), of solids and their surfaces. ARPES is also an ideal tool to address the question concerning the electron correlation effect on quasiparticle excitations in the low-dimensional (one- or two-dimensional) correlated electron systems. In this issue, we briefly introduce representative studies of ARPES and their fruitfulness from the free-electron-like three-dimensional systems to the low-dimensional strongly correlated electron systems. : 角度分解光電子分光法(ARPES)は,固体とその表面の電子構造の運動量依存性,すなわち電子構造のバンド分散 ε(k)を測定する有力な実験手法である.ARPES は低次元(一次元あるいは二次元)相関電子系における準粒子励起における電子相関の影響を調べるための理想的な手法でもある.本稿では,自由電子的な三次元系から低次元強相関電子系までの系に対するARPES の代表的な研究とその有効性について概説する.

著者

Lee J. D. Nagatomi T. (Translator) Mizutani G. (Translator) Endo K. (Translation Supervisor)

出版者

Surface Analysis Society of Japan

雑誌

Journal of Surface Analysis (ISSN:13411756)

巻号頁・発行日

vol.18, no.1, pp.36-57, 2011

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Novel potentials of photoemission electron spectroscopy have been recently enabled to be explored by an advent of upgraded relevant technology. The enhanced signal-to-noise ratio by an advancement of measurement technology has revived attention to the extrinsic loss beyond the sudden approximation of photoemission spectroscopy. The ultrashort laser pulses and their control by the state-of-the-art laser technologyhave given birth to the time-resolved photoemission spectroscopy. In this issue, we introduce somestudies of the extrinsic loss and the time-resolved mode of the photoemission spectroscopy. : 光電子分光法のもつポテンシャルは,関連技術の発展によってさらに高まっている.測定技術の進歩によって信号雑音(SN)比が向上したことで,従来の突然近似では取り扱えない,光電子分光のエキストリンシックなエネルギー損失に再び注目が集まるようになっている.また,超短レーザーパルスと最新のレーザー技術によって時間分解光電子分光法が実現された.本稿では,エキストリンシックなエネルギー損失と時間分解光電子分光に関するいくつかの研究について紹介する.