Dephasing of terahertz Bloch oscillations in a GaAs-based narrow-minigap superlattice excited by tunable pump photon energy
Dephasing of terahertz Bloch oscillations in a GaAs-based narrow-minigap superlattice excited by tunable pump photon energy
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DOI：
10.35848/1882-0786/abfa76
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发表时间：
2021-05
影响因子：
2.3
通讯作者：
T. Unuma;R. Abe
中科院分区：
文献类型：
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作者：
T. Unuma;R. Abe
我们通过太赫兹发射光谱研究了基于砷化镓的窄微隙超晶格中在子带间混合作用下的特殊布洛赫振荡。与在近乎孤立的微带中报道的万尼尔 - 斯塔克阶梯态情况相反，退相时间随着泵浦光子能量的增加而减少，并在某一能量处大幅下降。这种行为可归因于电子的纵光学（LO）声子发射，这些电子在面内具有过剩能量，并在导带第一微带中的直流偏置电场作用下被加速。我们的研究结果支持了最近用于解释振荡相位中伴随的π/2相移的微带输运模型的有效性。
We investigate peculiar Bloch oscillations under interminiband mixing in a GaAs-based narrow-minigap superlattice by terahertz emission spectroscopy. The dephasing time decreases with increasing pump photon energy and drops substantially at a certain energy, in contrast to that reported for Wannier–Stark ladder states in a nearly isolated miniband. This behavior can be ascribed to the LO phonon emission of electrons that are excited with in-plane excess energies and accelerated under dc bias electric field in the conduction first miniband. Our findings support the validity of the miniband transport model employed recently to account for an accompanying π/2 shift in the oscillation phase.