Photogalvanic probing of helical edge channels in two-dimensional HgTe topological insulators

K. M. Dantscher, D. A. Kozlov, M. T. Scherr, S. Gebert, J. Bärenfänger, M. V. Durnev, S. A. Tarasenko, V. V. Bel'Kov, N. N. Mikhailov, S. A. Dvoretsky, Z. D. Kvon, J. Ziegler, D. Weiss, S. D. Ganichev

Результат исследования: Научные публикации в периодических изданияхстатья

30 Цитирования (Scopus)

Аннотация

We report on the observation of a circular photogalvanic current excited by terahertz laser radiation in helical edge channels of two-dimensional (2D) HgTe topological insulators (TIs). The direction of the photocurrent reverses by switching the radiation polarization from a right-handed to a left-handed one and, for fixed photon helicity, is opposite for the opposite edges. The photocurrent is detected in a wide range of gate voltages. With decreasing the Fermi level below the conduction band bottom, the current emerges, reaches a maximum, decreases, changes its sign close to the charge neutrality point (CNP), and again rises. Conductance measured over a ≈3μm distance at CNP approaches 2e2/h, the value characteristic for ballistic transport in 2D TIs. The data reveal that the photocurrent is caused by photoionization of helical edge electrons to the conduction band. We discuss the microscopic model of this phenomenon and compare calculations with experimental data.

Язык оригиналаанглийский
Номер статьи201103
Число страниц5
ЖурналPhysical Review B
Том95
Номер выпуска20
DOI
СостояниеОпубликовано - 8 мая 2017

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  • Цитировать

    Dantscher, K. M., Kozlov, D. A., Scherr, M. T., Gebert, S., Bärenfänger, J., Durnev, M. V., Tarasenko, S. A., Bel'Kov, V. V., Mikhailov, N. N., Dvoretsky, S. A., Kvon, Z. D., Ziegler, J., Weiss, D., & Ganichev, S. D. (2017). Photogalvanic probing of helical edge channels in two-dimensional HgTe topological insulators. Physical Review B, 95(20), [201103]. https://doi.org/10.1103/PhysRevB.95.201103