People
Graduate Student
Mikhail Kravtsov
Title
PhD Student
Office Location
S9-08-01-37
I-FIM Publications:
2026 |
Zhou, Xiangyu; Gayduchenko, Igor; Kudriashov, Andrei; Shein, Kirill; Kuksov, Anton; Elesin, Leonid; Kravtsov, Mikhail; Shilov, Artur; Popova, Olga; Jana, Subhajit; Novoselov, Kostya S; Taniguchi, Takashi; Watanabe, Kenji; Goltsman, Gregory; Bandurin, Denis A Gate-Tunable Photoresponse of Graphene Josephson Junctions at Terahertz Frequencies NANO LETTERS, 26 (22), pp. 7435-7442, 2026, DOI: 10.1021/acs.nanolett.6c01483. @article{WOS:001776257400001, title = {Gate-Tunable Photoresponse of Graphene Josephson Junctions at Terahertz Frequencies}, author = {Xiangyu Zhou and Igor Gayduchenko and Andrei Kudriashov and Kirill Shein and Anton Kuksov and Leonid Elesin and Mikhail Kravtsov and Artur Shilov and Olga Popova and Subhajit Jana and Kostya S Novoselov and Takashi Taniguchi and Kenji Watanabe and Gregory Goltsman and Denis A Bandurin}, doi = {10.1021/acs.nanolett.6c01483}, times_cited = {0}, issn = {1530-6984}, year = {2026}, date = {2026-06-01}, journal = {NANO LETTERS}, volume = {26}, number = {22}, pages = {7435-7442}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Graphene Josephson junctions (JJs) are promising platforms for broadband quantum sensing because graphene combines frequency-independent absorption, ultralow electronic heat capacity, and weak electron-phonon coupling. While previous studies focused on microwave and infrared regimes, the terahertz (THz) range-where highly sensitive quantum detectors remain scarce-has largely remained unexplored. Here, we demonstrate a gate-tunable THz photoresponse in graphene JJs. Low-intensity THz illumination strongly suppresses the critical current, generating a pronounced photovoltage under current bias. From photovoltage measurements and independent electron thermometry, we extract a responsivity of 88 kV W-1 and a noise-equivalent power of 45 aW Hz(-1/2) at 1.7 K. In addition, the hysteretic regime that persists up to 0.9 K suggests a possible route toward single-photon THz detection above millikelvin temperatures. Our results establish graphene JJs as promising candidates for cryogenic THz quantum sensing.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene Josephson junctions (JJs) are promising platforms for broadband quantum sensing because graphene combines frequency-independent absorption, ultralow electronic heat capacity, and weak electron-phonon coupling. While previous studies focused on microwave and infrared regimes, the terahertz (THz) range-where highly sensitive quantum detectors remain scarce-has largely remained unexplored. Here, we demonstrate a gate-tunable THz photoresponse in graphene JJs. Low-intensity THz illumination strongly suppresses the critical current, generating a pronounced photovoltage under current bias. From photovoltage measurements and independent electron thermometry, we extract a responsivity of 88 kV W-1 and a noise-equivalent power of 45 aW Hz(-1/2) at 1.7 K. In addition, the hysteretic regime that persists up to 0.9 K suggests a possible route toward single-photon THz detection above millikelvin temperatures. Our results establish graphene JJs as promising candidates for cryogenic THz quantum sensing.
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Nikolaev, Konstantin G; Ivanov, Artemii; Wen, Han; Wang, Qian; Kravtsov, Mikhail; Bandurin, Denis A; Karim, Nazmul; Novoselov, Kostya S; Andreeva, Daria V One-Spot Synthesized Crystalline Graphene/PANI for Wearable Ionic Transistor Textiles SMALL STRUCTURES, 7 (4), 2026, DOI: 10.1002/sstr.202500904. @article{WOS:001751311800005, title = {One-Spot Synthesized Crystalline Graphene/PANI for Wearable Ionic Transistor Textiles}, author = {Konstantin G Nikolaev and Artemii Ivanov and Han Wen and Qian Wang and Mikhail Kravtsov and Denis A Bandurin and Nazmul Karim and Kostya S Novoselov and Daria V Andreeva}, doi = {10.1002/sstr.202500904}, times_cited = {0}, year = {2026}, date = {2026-04-01}, journal = {SMALL STRUCTURES}, volume = {7}, number = {4}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Here, we report a one-spot, temperature-controlled AC electropolymerization strategy for converting graphene oxide and aniline into a crystalline, processable reduced graphene oxide (rGO)/polyaniline (PANI) composite for wearable ionic transistor textiles. By tuning the electropolymerization temperature from 4 degrees C to 55 degrees C under a low-frequency triangular AC waveform, followed by mild postreduction, conformal polycrystalline PANI nanodomains are grown directly on rGO sheets. Low-temperature synthesis yields the highest structural ordering and the lowest fraction of protonated imine species, directly linking growth conditions to mixed ionic-electronic transport behavior. The resulting rGO/PANI composite functions as an electrolyte-gated transistor with stable operation and amplified gate response. Furthermore, the composite can be stencil printed onto cotton textiles to realize ratiometric Na+/K+ sensing at constant ionic strength, highlighting its potential for scalable, wearable ion-sensing architectures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Here, we report a one-spot, temperature-controlled AC electropolymerization strategy for converting graphene oxide and aniline into a crystalline, processable reduced graphene oxide (rGO)/polyaniline (PANI) composite for wearable ionic transistor textiles. By tuning the electropolymerization temperature from 4 degrees C to 55 degrees C under a low-frequency triangular AC waveform, followed by mild postreduction, conformal polycrystalline PANI nanodomains are grown directly on rGO sheets. Low-temperature synthesis yields the highest structural ordering and the lowest fraction of protonated imine species, directly linking growth conditions to mixed ionic-electronic transport behavior. The resulting rGO/PANI composite functions as an electrolyte-gated transistor with stable operation and amplified gate response. Furthermore, the composite can be stencil printed onto cotton textiles to realize ratiometric Na+/K+ sensing at constant ionic strength, highlighting its potential for scalable, wearable ion-sensing architectures.
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2025 |
Kravtsov, M; Shilov, A L; Yang, Y; Pryadilin, T; Kashchenko, M A; Popova, O; Titova, M; Voropaev, D; Wang, Y; Shein, K; Gayduchenko, I; Goltsman, G N; Lukianov, M; Kudriashov, A; Taniguchi, T; Watanabe, K; Svintsov, D A; Adam, S; Novoselov, K S; Principi, A; Bandurin, D A Viscous terahertz photoconductivity of hydrodynamic electrons in graphene 18 NATURE NANOTECHNOLOGY, 20 (1), pp. 51+, 2025, DOI: 10.1038/s41565-024-01795-y. @article{WOS:001330508900002, title = {Viscous terahertz photoconductivity of hydrodynamic electrons in graphene}, author = {M Kravtsov and A L Shilov and Y Yang and T Pryadilin and M A Kashchenko and O Popova and M Titova and D Voropaev and Y Wang and K Shein and I Gayduchenko and G N Goltsman and M Lukianov and A Kudriashov and T Taniguchi and K Watanabe and D A Svintsov and S Adam and K S Novoselov and A Principi and D A Bandurin}, doi = {10.1038/s41565-024-01795-y}, times_cited = {18}, issn = {1748-3387}, year = {2025}, date = {2025-01-01}, journal = {NATURE NANOTECHNOLOGY}, volume = {20}, number = {1}, pages = {51+}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively. Here we report a qualitative deviation from the standard behaviour in doped metallic graphene. We show that Dirac electrons exposed to continuous-wave terahertz (THz) radiation can be thermally decoupled from the lattice, which activates hydrodynamic electron transport. In this regime, the resistance of graphene constrictions experiences a decrease caused by the THz-driven superballistic flow of correlated electrons. We analyse the dependencies of the negative photoresistance on the carrier density, and the radiation power, and show that our superballistic devices operate as sensitive phonon-cooled bolometers and can thus offer, in principle, a picosecond-scale response time. Beyond their fundamental implications, our findings underscore the practicality of electron hydrodynamics in designing ultra-fast THz sensors and electron thermometers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Light incident upon materials can induce changes in their electrical conductivity, a phenomenon referred to as photoresistance. In semiconductors, the photoresistance is negative, as light-induced promotion of electrons across the bandgap enhances the number of charge carriers participating in transport. In superconductors and normal metals, the photoresistance is positive because of the destruction of the superconducting state and enhanced momentum-relaxing scattering, respectively. Here we report a qualitative deviation from the standard behaviour in doped metallic graphene. We show that Dirac electrons exposed to continuous-wave terahertz (THz) radiation can be thermally decoupled from the lattice, which activates hydrodynamic electron transport. In this regime, the resistance of graphene constrictions experiences a decrease caused by the THz-driven superballistic flow of correlated electrons. We analyse the dependencies of the negative photoresistance on the carrier density, and the radiation power, and show that our superballistic devices operate as sensitive phonon-cooled bolometers and can thus offer, in principle, a picosecond-scale response time. Beyond their fundamental implications, our findings underscore the practicality of electron hydrodynamics in designing ultra-fast THz sensors and electron thermometers.
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2024 |
Shilov, Artur L; Kashchenko, Mikhail A; Peralta, Pierre Pantaleon A; Wang, Yibo; Kravtsov, Mikhail; Kudriashov, Andrei; Zhan, Zhen; Taniguchi, Takashi; Watanabe, Kenji; Slizovskiy, Sergey; Novoselov, Kostya S; Fal'ko, Vladimir I; Guinea, Francisco; Bandurin, Denis A High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moire Superlattices ACS NANO, 18 (18), pp. 11769-11777, 2024, DOI: 10.1021/acsnano.3c13212. @article{WOS:001226272500001, title = {High-Mobility Compensated Semimetals, Orbital Magnetization, and Umklapp Scattering in Bilayer Graphene Moire Superlattices}, author = {Artur L Shilov and Mikhail A Kashchenko and Pierre Pantaleon A Peralta and Yibo Wang and Mikhail Kravtsov and Andrei Kudriashov and Zhen Zhan and Takashi Taniguchi and Kenji Watanabe and Sergey Slizovskiy and Kostya S Novoselov and Vladimir I Fal'ko and Francisco Guinea and Denis A Bandurin}, doi = {10.1021/acsnano.3c13212}, times_cited = {7}, issn = {1936-0851}, year = {2024}, date = {2024-04-01}, journal = {ACS NANO}, volume = {18}, number = {18}, pages = {11769-11777}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Twist-controlled moire superlattices (MSs) have emerged as a versatile platform for realizing artificial systems with complex electronic spectra. The combination of Bernal-stacked bilayer graphene (BLG) and hexagonal boron nitride (hBN) can give rise to an interesting MS, which has recently featured a set of unexpected behaviors, such as unconventional ferroelectricity and the electronic ratchet effect. Yet, the understanding of the electronic properties of BLG/hBN MS has, at present, remained fairly limited. Here, we combine magneto-transport and low-energy sub-THz excitation to gain insights into the properties of this MS. We demonstrate that the alignment between BLG and hBN crystal lattices results in the emergence of compensated semimetals at some integer fillings of the moire bands, separated by van Hove singularities where the Lifshitz transition occurs. A particularly pronounced semimetal develops when eight holes reside in the moire unit cell, where coexisting high-mobility electron and hole systems feature strong magnetoresistance reaching 2350% already at B = 0.25 T. Next, by measuring the THz-driven Nernst effect in remote bands, we observe valley splitting, indicating an orbital magnetization characterized by a strongly enhanced effective g(v)-factor of 340. Finally, using THz photoresistance measurements, we show that the high-temperature conductivity of the BLG/hBN MS is limited by electron-electron umklapp processes. Our multifaceted analysis introduces THz-driven magnetotransport as a convenient tool to probe the band structure and interaction effects in van der Waals materials and provides a comprehensive understanding of the BLG/hBN MS.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Twist-controlled moire superlattices (MSs) have emerged as a versatile platform for realizing artificial systems with complex electronic spectra. The combination of Bernal-stacked bilayer graphene (BLG) and hexagonal boron nitride (hBN) can give rise to an interesting MS, which has recently featured a set of unexpected behaviors, such as unconventional ferroelectricity and the electronic ratchet effect. Yet, the understanding of the electronic properties of BLG/hBN MS has, at present, remained fairly limited. Here, we combine magneto-transport and low-energy sub-THz excitation to gain insights into the properties of this MS. We demonstrate that the alignment between BLG and hBN crystal lattices results in the emergence of compensated semimetals at some integer fillings of the moire bands, separated by van Hove singularities where the Lifshitz transition occurs. A particularly pronounced semimetal develops when eight holes reside in the moire unit cell, where coexisting high-mobility electron and hole systems feature strong magnetoresistance reaching 2350% already at B = 0.25 T. Next, by measuring the THz-driven Nernst effect in remote bands, we observe valley splitting, indicating an orbital magnetization characterized by a strongly enhanced effective g(v)-factor of 340. Finally, using THz photoresistance measurements, we show that the high-temperature conductivity of the BLG/hBN MS is limited by electron-electron umklapp processes. Our multifaceted analysis introduces THz-driven magnetotransport as a convenient tool to probe the band structure and interaction effects in van der Waals materials and provides a comprehensive understanding of the BLG/hBN MS.
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