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Kumar N, Surovtsev NV, Yunin PA, Ishchenko DV, Milekhin IA, Lebedev SP, Lebedev AA, Tereshchenko OE. Raman scattering spectroscopy of MBE grown thin film topological insulator Bi 2-xSb xTe 3-ySe y. Phys Chem Chem Phys 2024; 26:13497-13505. [PMID: 38651229 DOI: 10.1039/d4cp01169d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates i.e., Si (111) and SiC/graphene with Bi0.7Sb1.6Te1.8Se0.9 and Bi0.9Sb1.5Te1.8Se1.1, respectively. The crystallographic properties of BSTS films were investigated via X-ray diffraction, which showed the strongest reflections from the (0 0 l) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate. Polarization dependent Raman spectroscopy showed a weak appearance of the Ag mode in cross--polarized geometry. In contrast, a strong Eg mode was observed in both parallel and cross-polarized geometries which correspond to the rhombohedral crystal symmetry of BSTS films. A redshift of Ag and Eg modes was observed in the Raman spectra of BSTS films grown on the Si substrate, compared to those on SiC/graphene, which was directly associated with the unit cell parameter and composition of the films. Raman spectra showed four fundamental modes with asymmetric line shape, and deconvolution of the peaks resulted in additional modes in both the BSTS thin films. The sum of relative ratios of linewidths of fundamental modes (Ag and Eg) of BSTS films grown on Si substrate was lower, indicating a more ordered structure with lower contribution of defects as compared to BSTS film grown on SiC/graphene substrate.
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Affiliation(s)
- N Kumar
- Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090, Russia.
- Faculty of Physics, Tomsk State University, 36 Lenin Ave., Tomsk 634050, Russia
| | - N V Surovtsev
- Institute of Automation and Electrometry, SB, RAS, Novosibirsk, 630090, Russia
| | - P A Yunin
- Institute for Physics of Microstructures, RAS, Afonino, Nizhny Novgorod 603087, Russia
- Faculty of Radiophysics, Lobachevsky State University, Nizhny Novgorod 603950, Russia
| | - D V Ishchenko
- Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090, Russia.
| | - I A Milekhin
- Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090, Russia.
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - S P Lebedev
- Ioffe Institute, 194021 St. Petersburg, Russia
| | - A A Lebedev
- Ioffe Institute, 194021 St. Petersburg, Russia
| | - O E Tereshchenko
- Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090, Russia.
- Synchrotron Radiation Facility SKIF, Boreskov Institute of Catalysis, SB, RAS, Koltsovo 630559, Russia
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2
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Reimann J, Sumida K, Kakoki M, Kokh KA, Tereshchenko OE, Kimura A, Güdde J, Höfer U. Ultrafast electron dynamics in a topological surface state observed in two-dimensional momentum space. Sci Rep 2023; 13:5796. [PMID: 37032349 PMCID: PMC10083179 DOI: 10.1038/s41598-023-32811-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/31/2023] [Indexed: 04/11/2023] Open
Abstract
We study ultrafast population dynamics in the topological surface state of Sb[Formula: see text]Te[Formula: see text] in two-dimensional momentum space with time- and angle-resolved two-photon photoemission spectroscopy. Linearly polarized mid-infrared pump pulses are used to permit a direct optical excitation across the Dirac point. We show that this resonant excitation is strongly enhanced within the Dirac cone along three of the six [Formula: see text]-[Formula: see text] directions and results in a macroscopic photocurrent when the plane of incidence is aligned along a [Formula: see text]-[Formula: see text] direction. Our experimental approach makes it possible to disentangle the decay of transiently excited population and photocurent by elastic and inelastic electron scattering within the full Dirac cone in unprecedented detail. This is utilized to show that doping of Sb[Formula: see text]Te[Formula: see text] by vanadium atoms strongly enhances inelastic electron scattering to lower energies, but only scarcely affects elastic scattering around the Dirac cone.
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Affiliation(s)
- J Reimann
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany
| | - K Sumida
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
- Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo, Hyogo, 679-5148, Japan
| | - M Kakoki
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - K A Kokh
- V.S. Sobolev Institute of Geology and Mineralogy SB RAS, 630090, Novosibirsk, Russian Federation
| | - O E Tereshchenko
- Rzhanov Institute of Semiconductor Physics SB RAS, 630090, Novosibirsk, Russian Federation
| | - A Kimura
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), 1-3-2 Kagamiyama, Higashi-Hiroshima, 739-8511, Japan
| | - J Güdde
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany.
| | - U Höfer
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, 35032, Marburg, Germany
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3
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Ito S, Schüler M, Meierhofer M, Schlauderer S, Freudenstein J, Reimann J, Afanasiev D, Kokh KA, Tereshchenko OE, Güdde J, Sentef MA, Höfer U, Huber R. Build-up and dephasing of Floquet-Bloch bands on subcycle timescales. Nature 2023; 616:696-701. [PMID: 37046087 DOI: 10.1038/s41586-023-05850-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 02/15/2023] [Indexed: 04/14/2023]
Abstract
Strong light fields have created opportunities to tailor novel functionalities of solids1-5. Floquet-Bloch states can form under periodic driving of electrons and enable exotic quantum phases6-15. On subcycle timescales, lightwaves can simultaneously drive intraband currents16-29 and interband transitions18,19,30,31, which enable high-harmonic generation16,18,19,21,22,25,28-30 and pave the way towards ultrafast electronics. Yet, the interplay of intraband and interband excitations and their relation to Floquet physics have been key open questions as dynamical aspects of Floquet states have remained elusive. Here we provide this link by visualizing the ultrafast build-up of Floquet-Bloch bands with time-resolved and angle-resolved photoemission spectroscopy. We drive surface states on a topological insulator32,33 with mid-infrared fields-strong enough for high-harmonic generation-and directly monitor the transient band structure with subcycle time resolution. Starting with strong intraband currents, we observe how Floquet sidebands emerge within a single optical cycle; intraband acceleration simultaneously proceeds in multiple sidebands until high-energy electrons scatter into bulk states and dissipation destroys the Floquet bands. Quantum non-equilibrium calculations explain the simultaneous occurrence of Floquet states with intraband and interband dynamics. Our joint experiment and theory study provides a direct time-domain view of Floquet physics and explores the fundamental frontiers of ultrafast band-structure engineering.
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Affiliation(s)
- S Ito
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M Schüler
- Laboratory for Materials Simulations, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, University of Fribourg, Fribourg, Switzerland
| | - M Meierhofer
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - S Schlauderer
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - J Freudenstein
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - J Reimann
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - D Afanasiev
- Department of Physics, University of Regensburg, Regensburg, Germany
| | - K A Kokh
- A.V. Rzhanov Institute of Semiconductor Physics and V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation
| | - O E Tereshchenko
- A.V. Rzhanov Institute of Semiconductor Physics and V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russian Federation
| | - J Güdde
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M A Sentef
- Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany.
| | - U Höfer
- Department of Physics, Philipps-University of Marburg, Marburg, Germany.
- Department of Physics, University of Regensburg, Regensburg, Germany.
| | - R Huber
- Department of Physics, University of Regensburg, Regensburg, Germany.
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4
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Zakirov ER, Kesler VG, Sidorov GY, Golyashov VA, Tereshchenko OE, Marin DV, Yakushev MV. Wet Chemical Methods of HgCdTe Surface Treatment. J STRUCT CHEM+ 2023. [DOI: 10.1134/s0022476623030150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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5
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Rusetsky VS, Golyashov VA, Eremeev SV, Kustov DA, Rusinov IP, Shamirzaev TS, Mironov AV, Demin AY, Tereshchenko OE. New Spin-Polarized Electron Source Based on Alkali Antimonide Photocathode. Phys Rev Lett 2022; 129:166802. [PMID: 36306756 DOI: 10.1103/physrevlett.129.166802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
New spin-dependent photoemission properties of alkali antimonide semiconductor cathodes are predicted based on the detected optical spin orientation effect and DFT band structure calculations. Using these results, the Na_{2}KSb/Cs_{3}Sb heterostructure is designed as a spin-polarized electron source in combination with the Al_{0.11}Ga_{0.89}As target as a spin detector with spatial resolution. In the Na_{2}KSb/Cs_{3}Sb photocathode, spin-dependent photoemission properties were established through detection of a high degree of photoluminescence polarization and high polarization of the photoemitted electrons. It was found that the multi-alkali photocathode can provide electron beams with emittance very close to the limits imposed by the electron thermal energy. The vacuum tablet-type sources of spin-polarized electrons have been proposed for accelerators, which can exclude the construction of the photocathode growth chambers for photoinjectors.
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Affiliation(s)
- V S Rusetsky
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- CJSC "Ekran FEP", Novosibirsk 630060, Russia
| | - V A Golyashov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- Synchrotron radiation facility SKIF, Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Kol'tsovo 630559, Russia
- Novosibirsk State University, Novosibirsk 630090 Russia
| | - S V Eremeev
- Institute of Strength Physics and Materials Science, Tomsk 634055, Russia
| | - D A Kustov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - I P Rusinov
- Tomsk State University, Tomsk 634050, Russia
| | - T S Shamirzaev
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090 Russia
| | - A V Mironov
- CJSC "Ekran FEP", Novosibirsk 630060, Russia
| | - A Yu Demin
- CJSC "Ekran FEP", Novosibirsk 630060, Russia
| | - O E Tereshchenko
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- Synchrotron radiation facility SKIF, Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Kol'tsovo 630559, Russia
- Novosibirsk State University, Novosibirsk 630090 Russia
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6
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Tarasov AS, Golyashov VA, Akhundov IO, Ishchenko DV, Kozhukhov AS, Kokh KA, Tereshchenko OE. Preparation of an Atomically Clean and Structurally Ordered Bi2Se3 (0001) Surface without Molecular Beams and Vacuum Cleaving. Russ J Phys Chem B 2022. [DOI: 10.1134/s1990793122030241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Shikin AM, Rybkina AA, Estyunin DA, Klimovskikh II, Rybkin AG, Filnov SO, Koroleva AV, Shevchenko EV, Likholetova MV, Voroshnin VY, Petukhov AE, Kokh KA, Tereshchenko OE, Petaccia L, Di Santo G, Kumar S, Kimura A, Skirdkov PN, Zvezdin KA, Zvezdin AK. Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI. Sci Rep 2021; 11:23332. [PMID: 34857800 PMCID: PMC8639783 DOI: 10.1038/s41598-021-02493-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/27/2021] [Indexed: 12/01/2022] Open
Abstract
Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.
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Affiliation(s)
- A M Shikin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.
| | - A A Rybkina
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - D A Estyunin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - I I Klimovskikh
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - A G Rybkin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - S O Filnov
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - A V Koroleva
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - E V Shevchenko
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - M V Likholetova
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - V Yu Voroshnin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, 12489, Berlin, Germany
| | - A E Petukhov
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - K A Kokh
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Kemerovo State University, Kemerovo, 650000, Russia.,Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia
| | - O E Tereshchenko
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia.,A. V. Rzhanov Institute of Semiconductor Physics, Novosibirsk, 630090, Russia
| | - L Petaccia
- Elettra Sincrotrone Trieste, 34149, Trieste, Italy
| | - G Di Santo
- Elettra Sincrotrone Trieste, 34149, Trieste, Italy
| | - S Kumar
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-0046, Japan
| | - A Kimura
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - P N Skirdkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - K A Zvezdin
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - A K Zvezdin
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow, 119991, Russia
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8
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Schmid CP, Weigl L, Grössing P, Junk V, Gorini C, Schlauderer S, Ito S, Meierhofer M, Hofmann N, Afanasiev D, Crewse J, Kokh KA, Tereshchenko OE, Güdde J, Evers F, Wilhelm J, Richter K, Höfer U, Huber R. Tunable non-integer high-harmonic generation in a topological insulator. Nature 2021; 593:385-390. [PMID: 34012087 DOI: 10.1038/s41586-021-03466-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/17/2021] [Indexed: 02/04/2023]
Abstract
When intense lightwaves accelerate electrons through a solid, the emerging high-order harmonic (HH) radiation offers key insights into the material1-11. Sub-optical-cycle dynamics-such as dynamical Bloch oscillations2-5, quasiparticle collisions6,12, valley pseudospin switching13 and heating of Dirac gases10-leave fingerprints in the HH spectra of conventional solids. Topologically non-trivial matter14,15 with invariants that are robust against imperfections has been predicted to support unconventional HH generation16-20. Here we experimentally demonstrate HH generation in a three-dimensional topological insulator-bismuth telluride. The frequency of the terahertz driving field sharply discriminates between HH generation from the bulk and from the topological surface, where the unique combination of long scattering times owing to spin-momentum locking17 and the quasi-relativistic dispersion enables unusually efficient HH generation. Intriguingly, all observed orders can be continuously shifted to arbitrary non-integer multiples of the driving frequency by varying the carrier-envelope phase of the driving field-in line with quantum theory. The anomalous Berry curvature warranted by the non-trivial topology enforces meandering ballistic trajectories of the Dirac fermions, causing a hallmark polarization pattern of the HH emission. Our study provides a platform to explore topology and relativistic quantum physics in strong-field control, and could lead to non-dissipative topological electronics at infrared frequencies.
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Affiliation(s)
- C P Schmid
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - L Weigl
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - P Grössing
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - V Junk
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - C Gorini
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.,Université Paris-Saclay, CEA, CNRS, SPEC, Gif-sur-Yvette, France
| | - S Schlauderer
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - S Ito
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - M Meierhofer
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - N Hofmann
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - D Afanasiev
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany
| | - J Crewse
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - K A Kokh
- V.S. Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russia.,Novosibirsk State University, Novosibirsk, Russia
| | - O E Tereshchenko
- Novosibirsk State University, Novosibirsk, Russia.,A.V. Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk, Russia
| | - J Güdde
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - F Evers
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany
| | - J Wilhelm
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.
| | - K Richter
- Institute of Theoretical Physics, University of Regensburg, Regensburg, Germany.
| | - U Höfer
- Department of Physics, Philipps-University of Marburg, Marburg, Germany
| | - R Huber
- Institute of Experimental and Applied Physics, University of Regensburg, Regensburg, Germany.
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9
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Golyashov VA, Rusetsky VS, Shamirzaev TS, Dmitriev DV, Kislykh NV, Mironov AV, Aksenov VV, Tereshchenko OE. Spectral detection of spin-polarized ultra low-energy electrons in semiconductor heterostructures. Ultramicroscopy 2020; 218:113076. [PMID: 32738565 DOI: 10.1016/j.ultramic.2020.113076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/07/2020] [Accepted: 07/11/2020] [Indexed: 10/23/2022]
Abstract
The circularly polarized cathodoluminescence (CL) technique has been used to study the free spin-polarized electron injection in semiconductor heterostructures with quantum wells (QWs). A polarized electron beam was created by the emission of optically oriented electrons from the p-GaAs(Cs,O) negative electron affinity (NEA) photocathode. The prepared beam was injected in a semiconductor QW target, which was activated by cesium and oxygen to reduce the work function. To study the spin-dependent injection, we developed a spin-detector prototype, which consists of a compact proximity focused vacuum tube with the source and target placed parallel to each other on the opposite ends of the vacuum tube (photodiode). The injection of polarized low-energy electrons into the target by varying the kinetic energy in the range of 0.5-5.0 eV and temperature in the range of 90-300 K was studied. The CL was polarized to 2 % by the injection of 20 % spin-polarized electron beam with the energy of 0.5 eV at room temperature. The asymmetry (Sherman function) of spin detection was estimated. It was shown that the dependence of the CL polarization degree on the injected electron energy is satisfactory described by the model that considers the electron spin relaxation in the heterostructure matrix and QWs. The results demonstrate that semiconductor detectors are promising for the spin-polarimetry applications based on the optical detection of free-electron spin polarization.
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Affiliation(s)
- V A Golyashov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk, 630090, Russian Federation
| | - V S Rusetsky
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; CJSC EKRAN-FEP, Novosibirsk 630060, Russian Federation
| | - T S Shamirzaev
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk, 630090, Russian Federation
| | - D V Dmitriev
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
| | - N V Kislykh
- CJSC EKRAN-FEP, Novosibirsk 630060, Russian Federation
| | - A V Mironov
- CJSC EKRAN-FEP, Novosibirsk 630060, Russian Federation
| | - V V Aksenov
- CJSC EKRAN-FEP, Novosibirsk 630060, Russian Federation
| | - O E Tereshchenko
- Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Novosibirsk, 630090, Russian Federation.
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10
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Antonova IV, Nebogatikova NA, Kokh KA, Kustov DA, Soots RA, Golyashov VA, Tereshchenko OE. Electrochemically exfoliated thin Bi 2Se 3 films and van der Waals heterostructures Bi 2Se 3/graphene. Nanotechnology 2020; 31:125602. [PMID: 31778984 DOI: 10.1088/1361-6528/ab5cd5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Thin Bi2Se3 flakes with few nanometer thicknesses and sized up to 350 μm were created by using electrochemical splitting from high-quality Bi2Se3 bulk monocrystals. The dependence of film resistance on the Bi2Se3 flake thickness demonstrates that, at room temperature, the bulk conductivity becomes negligible in comparison with the surface conductivity for films with thicknesses lower than 80 nm. Unexpectedly, all these films demonstrated p-type conductivity. The doping effect with sulfur or sulfur-related radicals during electrochemical exfoliation is suggested for the p-type conductivity of the exfoliated Bi2Se3 films. The formation of 2-8 nm films was predominantly found. Van der Waals (vdW) heterostructures of Bi2Se3/Graphene/SiO2/Si were created and their properties were compared with that of Bi2Se3 on the SiO2/Si substrate. The increase of the conductivity and carrier mobility in Bi2Se3 flakes of 3-5 times was found for vdW heterostructures with graphene. Thin Bi2Se3 films are potentially interesting for applications for spintronics, nano- and optoelectronics.
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Affiliation(s)
- I V Antonova
- Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk, 630090, Russia. Novosibirsk State University, Novosibirsk, 630090, Russia. Novosibirsk State Technical University, Novosibirsk, 630073, Russia
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11
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Reimann J, Schlauderer S, Schmid CP, Langer F, Baierl S, Kokh KA, Tereshchenko OE, Kimura A, Lange C, Güdde J, Höfer U, Huber R. Subcycle observation of lightwave-driven Dirac currents in a topological surface band. Nature 2018; 562:396-400. [DOI: 10.1038/s41586-018-0544-x] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/26/2018] [Indexed: 11/09/2022]
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12
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13
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Sumida K, Ishida Y, Zhu S, Ye M, Pertsova A, Triola C, Kokh KA, Tereshchenko OE, Balatsky AV, Shin S, Kimura A. Prolonged duration of nonequilibrated Dirac fermions in neutral topological insulators. Sci Rep 2017; 7:14080. [PMID: 29074864 PMCID: PMC5658381 DOI: 10.1038/s41598-017-14308-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 10/09/2017] [Indexed: 12/03/2022] Open
Abstract
Topological insulators (TIs) possess spin-polarized Dirac fermions on their surface but their unique properties are often masked by residual carriers in the bulk. Recently, (Sb1−xBix)2Te3 was introduced as a non-metallic TI whose carrier type can be tuned from n to p across the charge neutrality point. By using time- and angle-resolved photoemission spectroscopy, we investigate the ultrafast carrier dynamics in the series of (Sb1−xBix)2Te3. The Dirac electronic recovery of ∼10 ps at most in the bulk-metallic regime elongated to >400 ps when the charge neutrality point was approached. The prolonged nonequilibration is attributed to the closeness of the Fermi level to the Dirac point and to the high insulation of the bulk. We also discuss the feasibility of observing excitonic instability of (Sb1−xBix)2Te3.
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Affiliation(s)
- K Sumida
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
| | - Y Ishida
- ISSP, University of Tokyo, 5-1-5, Kashiwa-no-ha, Chiba 277-8581, Japan.
| | - S Zhu
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - M Ye
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Chang Ning Road, Shanghai 200050, China
| | - A Pertsova
- Nordita, Roslagstullsbacken 23, SE-106 91, Stockholm, Sweden.,Center for Quantum Materials (CQM), KTH and Nordita, Stockholm, Sweden
| | - C Triola
- Nordita, Roslagstullsbacken 23, SE-106 91, Stockholm, Sweden.,Center for Quantum Materials (CQM), KTH and Nordita, Stockholm, Sweden
| | - K A Kokh
- Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Koptyuga pr. 3, 630090, Novosibirsk, Russia.,Novosibirsk State University, ul. Pirogova 2, 630090, Novosibirsk, Russia.,Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - O E Tereshchenko
- Novosibirsk State University, ul. Pirogova 2, 630090, Novosibirsk, Russia.,Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 13, 630090, Novosibirsk, Russia
| | - A V Balatsky
- Nordita, Roslagstullsbacken 23, SE-106 91, Stockholm, Sweden.,Center for Quantum Materials (CQM), KTH and Nordita, Stockholm, Sweden.,Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA.,ETH Institute for Theoretical Studies, ETH Zurich, 8092 Zurich, Switzerland.,Department of Physics, University of Connecticut, Storrs, CT 06269, USA
| | - S Shin
- ISSP, University of Tokyo, 5-1-5, Kashiwa-no-ha, Chiba 277-8581, Japan
| | - A Kimura
- Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
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14
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Klimovskikh II, Shikin AM, Otrokov MM, Ernst A, Rusinov IP, Tereshchenko OE, Golyashov VA, Sánchez-Barriga J, Varykhalov AY, Rader O, Kokh KA, Chulkov EV. Giant Magnetic Band Gap in the Rashba-Split Surface State of Vanadium-Doped BiTeI: A Combined Photoemission and Ab Initio Study. Sci Rep 2017; 7:3353. [PMID: 28611416 PMCID: PMC5469768 DOI: 10.1038/s41598-017-03507-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/28/2017] [Indexed: 12/01/2022] Open
Abstract
One of the most promising platforms for spintronics and topological quantum computation is the two-dimensional electron gas (2DEG) with strong spin-orbit interaction and out-of-plane ferromagnetism. In proximity to an s-wave superconductor, such 2DEG may be driven into a topologically non-trivial superconducting phase, predicted to support zero-energy Majorana fermion modes. Using angle-resolved photoemission spectroscopy and ab initio calculations, we study the 2DEG at the surface of the vanadium-doped polar semiconductor with a giant Rashba-type splitting, BiTeI. We show that the vanadium-induced magnetization in the 2DEG breaks time-reversal symmetry, lifting Kramers degeneracy of the Rashba-split surface state at the Brillouin zone center via formation of a huge gap of about 90 meV. As a result, the constant energy contour inside the gap consists of only one circle with spin-momentum locking. These findings reveal a great potential of the magnetically-doped semiconductors with a giant Rashba-type splitting for realization of novel states of matter.
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Affiliation(s)
- I I Klimovskikh
- Saint Petersburg State University, 198504, Saint Petersburg, Russia.
| | - A M Shikin
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
| | - M M Otrokov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Tomsk State University, 634050, Tomsk, Russia
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
| | - A Ernst
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
- Institut für Theoretische Physik, Johannes Kepler Universität, A 4040, Linz, Austria
| | - I P Rusinov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Tomsk State University, 634050, Tomsk, Russia
| | - O E Tereshchenko
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- A.V. Rzhanov Institute of Semiconductor Physics, 630090, Novosibirsk, Russia
- Novosibirsk State University, 630090, Novosibirsk, Russia
| | - V A Golyashov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- A.V. Rzhanov Institute of Semiconductor Physics, 630090, Novosibirsk, Russia
| | - J Sánchez-Barriga
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - A Yu Varykhalov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - O Rader
- Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - K A Kokh
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Novosibirsk State University, 630090, Novosibirsk, Russia
- V.S. Sobolev Institute of Geology and Mineralogy, 630090, Novosibirsk, Russia
| | - E V Chulkov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Tomsk State University, 634050, Tomsk, Russia
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain
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15
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Klimovskikh II, Sostina D, Petukhov A, Rybkin AG, Eremeev SV, Chulkov EV, Tereshchenko OE, Kokh KA, Shikin AM. Spin-resolved band structure of heterojunction Bi-bilayer/3D topological insulator in the quantum dimension regime in annealed Bi 2Te 2.4Se 0.6. Sci Rep 2017; 7:45797. [PMID: 28378826 PMCID: PMC5381095 DOI: 10.1038/srep45797] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/02/2017] [Indexed: 11/08/2022] Open
Abstract
Two- and three-dimensional topological insulators are the key materials for the future nanoelectronic and spintronic devices and quantum computers. By means of angle- and spin-resolved photoemission spectroscopy we study the electronic and spin structure of the Bi-bilayer/3D topological insulator in quantum tunneling regime formed under the short annealing of Bi2Te2.4Se0.6. Owing to the temperature-induced restructuring of the topological insulator's surface quintuple layers, the hole-like spin-split Bi-bilayer bands and the parabolic electronic-like state are observed instead of the Dirac cone. Scanning Tunneling Microscopy and X-ray Photoemission Spectroscopy measurements reveal the appearance of the Bi2 terraces at the surface under the annealing. The experimental results are supported by density functional theory calculations, predicting the spin-polarized Bi-bilayer bands interacting with the quintuple-layers-derived states. Such an easily formed heterostructure promises exciting applications in spin transport devices and low-energy electronics.
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Affiliation(s)
| | - D. Sostina
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
| | - A. Petukhov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
| | - A. G. Rybkin
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
| | - S. V. Eremeev
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Institute of Strength Physics and Materials Science, 634055, Tomsk, Russia
- Tomsk State University, 634050, Tomsk, Russia
| | - E. V. Chulkov
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Tomsk State University, 634050, Tomsk, Russia
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Basque Country, Spain
- Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM - MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Basque Country, Spain
| | - O. E. Tereshchenko
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- A.V. Rzhanov Institute of Semiconductor Physics, 630090, Novosibirsk, Russia
- Novosibirsk State University, 630090, Novosibirsk, Russia
| | - K. A. Kokh
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Novosibirsk State University, 630090, Novosibirsk, Russia
- V.S. Sobolev Institute of Geology and Mineralogy, 630090, Novosibirsk, Russia
| | - A. M. Shikin
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
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16
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Bathon T, Sessi P, Kokh KA, Tereshchenko OE, Bode M. Systematics of molecular self-assembled networks at topological insulators surfaces. Nano Lett 2015; 15:2442-2447. [PMID: 25734260 DOI: 10.1021/nl5048434] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The success of topological insulators (TI) in creating devices with unique functionalities is directly connected to the ability of coupling their helical spin states to well-defined perturbations. However, up to now, TI-based heterostructures always resulted in very disordered interfaces, characterized by strong mesoscopic fluctuations of the chemical potential that make the spin-momentum locking ill-defined over length scales of few nanometers or even completely destroy topological states. These limitations call for the ability to control topological interfaces with atomic precision. Here, we demonstrate that molecular self-assembly processes driven by inherent interactions among the constituents offer the opportunity to create well-defined networks at TIs surfaces. Even more remarkably, we show that the symmetry of the overlayer can be finely controlled by appropriate chemical modifications. By analyzing the influence of the molecules on the TI electronic properties, we rationalize our results in terms of the charge redistribution taking place at the interface. Overall, our approach offers a precise and fast way to produce tailor-made nanoscale surface landscapes. In particular, our findings make organic materials ideal TIs counterparts, because they offer the possibility to chemically tune both electronic and magnetic properties within the same family of molecules, thereby bringing us a significant step closer toward an application of this fascinating class of materials.
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Affiliation(s)
- T Bathon
- †Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - P Sessi
- †Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - K A Kokh
- ‡V. S. Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
- §Novosibirsk State University, 630090 Novosibirsk, Russia
| | - O E Tereshchenko
- §Novosibirsk State University, 630090 Novosibirsk, Russia
- ∥A. V. Rzanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - M Bode
- †Physikalisches Institut, Experimentelle Physik II, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- ⊥Wilhelm Conrad Röntgen-Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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17
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Roy S, Meyerheim HL, Ernst A, Mohseni K, Tusche C, Vergniory MG, Menshchikova TV, Otrokov MM, Ryabishchenkova AG, Aliev ZS, Babanly MB, Kokh KA, Tereshchenko OE, Chulkov EV, Schneider J, Kirschner J. Tuning the Dirac point position in Bi(2)Se(3)(0001) via surface carbon doping. Phys Rev Lett 2014; 113:116802. [PMID: 25259997 DOI: 10.1103/physrevlett.113.116802] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Indexed: 06/03/2023]
Abstract
Angular resolved photoemission spectroscopy in combination with ab initio calculations show that trace amounts of carbon doping of the Bi_{2}Se_{3} surface allows the controlled shift of the Dirac point within the bulk band gap. In contrast to expectation, no Rashba-split two-dimensional electron gas states appear. This unique electronic modification is related to surface structural modification characterized by an expansion of the top Se-Bi spacing of ≈11% as evidenced by surface x-ray diffraction. Our results provide new ways to tune the surface band structure of topological insulators.
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Affiliation(s)
- Sumalay Roy
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - A Ernst
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig, Germany
| | - K Mohseni
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - C Tusche
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
| | - M G Vergniory
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain
| | - T V Menshchikova
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Tomsk State University, 634050 Tomsk, Russia
| | - M M Otrokov
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain and Tomsk State University, 634050 Tomsk, Russia
| | | | - Z S Aliev
- Baku State University, General and Inorganic Chemistry Department, AZ1148 Baku, Azerbaijan
| | - M B Babanly
- Baku State University, General and Inorganic Chemistry Department, AZ1148 Baku, Azerbaijan
| | - K A Kokh
- Institute of Geology and Mineralogy SB RAS, 630090 Novosibirsk, Russia
| | - O E Tereshchenko
- Institute of Semiconductor Physics SB RAS, and Novosibirsk State University, 630090 Novosibirsk, Russia
| | - E V Chulkov
- Donostia International Physics Center (DIPC), 20018 San Sebastián/Donostia, Spain and Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20080 San Sebastián/Donostia, Spain
| | - J Schneider
- Department für Geowissenschaften Ludwig-Maximilians Universität München, D-80333 München, Germany
| | - J Kirschner
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle, Germany
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18
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Sessi P, Bathon T, Kokh KA, Tereshchenko OE, Bode M. Probing the electronic properties of individual MnPc molecules coupled to topological states. Nano Lett 2014; 14:5092-5096. [PMID: 25111590 DOI: 10.1021/nl5017893] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Hybrid organic/inorganic interfaces have been widely reported to host emergent properties that go beyond those of their single constituents. Coupling molecules to the recently discovered topological insulators, which possess linearly dispersing and spin-momentum-locked Dirac fermions, may offer a promising platform toward new functionalities. Here, we report a scanning tunneling microscopy and spectroscopy study of the prototypical interface between MnPc molecules and a Bi2Te3 surface. MnPc is found to bind stably to the substrate through its central Mn atom. The adsorption process is only accompanied by a minor charge transfer across the interface, resulting in a moderately n-doped Bi2Te3 surface. More remarkably, topological states remain completely unaffected by the presence of the molecules, as evidenced by the absence of scattering patterns around adsorption sites. Interestingly, we show that, while the HOMO and LUMO orbitals closely resemble those of MnPc in the gas phase, a new hybrid state emerges through interaction with the substrate. Our results pave the way toward hybrid organic-topological insulator heterostructures, which may unveil a broad range of exciting and unknown phenomena.
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Affiliation(s)
- P Sessi
- Physikalisches Institut, Experimentelle Physik 2, Universität Würzburg , Am Hubland, 97074 Würzburg, Germany
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19
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Kokh KA, Makarenko SV, Golyashov VA, Shegai OA, Tereshchenko OE. Melt growth of bulk Bi2Te3crystals with a natural p–n junction. CrystEngComm 2014. [DOI: 10.1039/c3ce42026d] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Luo CW, Wang HJ, Ku SA, Chen HJ, Yeh TT, Lin JY, Wu KH, Juang JY, Young BL, Kobayashi T, Cheng CM, Chen CH, Tsuei KD, Sankar R, Chou FC, Kokh KA, Tereshchenko OE, Chulkov EV, Andreev YM, Gu GD. Snapshots of Dirac fermions near the Dirac point in topological insulators. Nano Lett 2013; 13:5797-5802. [PMID: 24228733 DOI: 10.1021/nl4021842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The recent focus on topological insulators is due to the scientific interest in the new state of quantum matter as well as the technology potential for a new generation of THz optoelectronics, spintronics and quantum computations. It is important to elucidate the dynamics of the Dirac fermions in the topologically protected surface state. Hence we utilized a novel ultrafast optical pump mid-infrared probe to explore the dynamics of Dirac fermions near the Dirac point. The femtosecond snapshots of the relaxation process were revealed by the ultrafast optics. Specifically, the Dirac fermion-phonon coupling strength in the Dirac cone was found to increase from 0.08 to 0.19 while Dirac fermions were away from the Dirac point into higher energy states. Further, the energy-resolved transient reflectivity spectra disclosed the energy loss rate of Dirac fermions at room temperature was about 1 meV/ps. These results are crucial to the design of Dirac fermion devices.
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Affiliation(s)
- C W Luo
- Department of Electrophysics and ‡Institute of Physics, National Chiao Tung University , Hsinchu, Taiwan
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Mauchain J, Ohtsubo Y, Hajlaoui M, Papalazarou E, Marsi M, Taleb-Ibrahimi A, Faure J, Kokh KA, Tereshchenko OE, Eremeev SV, Chulkov EV, Perfetti L. Circular dichroism and superdiffusive transport at the surface of BiTeI. Phys Rev Lett 2013; 111:126603. [PMID: 24093286 DOI: 10.1103/physrevlett.111.126603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Indexed: 06/02/2023]
Abstract
We investigate the electronic states of BiTeI after the optical pumping with circularly polarized photons. Our data show that photoexcited electrons reach an internal thermalization within 300 fs of the arrival of the pump pulse. Instead, the dichroic contrast generated by the circularly polarized light relaxes on a time scale shorter than 80 fs. This result implies that orbital and spin polarization created by the circular pump pulse rapidly decays via manybody interaction. The persistent dichroism at longer delay times is due to the helicity dependence of superdiffussive transport. We ascribe it to the lack of inversion symmetry in an electronic system far from equilibrium conditions.
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Affiliation(s)
- J Mauchain
- Laboratoire de Physique des Solides, CNRS-UMR 8502, Université Paris-Sud, FR-91405 Orsay, France
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22
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Miyamoto K, Kimura A, Okuda T, Miyahara H, Kuroda K, Namatame H, Taniguchi M, Eremeev SV, Menshchikova TV, Chulkov EV, Kokh KA, Tereshchenko OE. Topological surface states with persistent high spin polarization across the Dirac point in Bi2Te2Se and Bi2Se2Te. Phys Rev Lett 2012; 109:166802. [PMID: 23215110 DOI: 10.1103/physrevlett.109.166802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Indexed: 06/01/2023]
Abstract
Helical spin textures with marked spin polarizations of topological surface states have been unveiled for the first time by state-of-the-art spin- and angle-resolved photoemission spectroscopy for two promising topological insulators, Bi(2)Te(2)Se and Bi(2)Se(2)Te. Their highly spin-polarized natures are found to be persistent across the Dirac point in both compounds. This novel finding paves a pathway to extending the utilization of topological surface states of these compounds for future spintronic applications.
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Affiliation(s)
- K Miyamoto
- Hiroshima Synchrotron Radiation Center, Hiroshima University, 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan.
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23
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Hogan C, Paget D, Tereshchenko OE, Del Sole R. Effect of adsorption of electronegative and electropositive elements on the surface optical anisotropy of GaAs(001). ACTA ACUST UNITED AC 2003. [DOI: 10.1002/pssc.200303838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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