People
Graduate Student
Leonid Elesin
Title
PhD Student
Research Interests
Condensed matter physics, 2D materials, twistronics, scanning probe microscopy
Research Group
Group Webpage
Office Location
S9-08-01-40
I-FIM Publications:
2026 |
Elesin, L; Shilov, A L; Kravtsov, M; Zhou, X; Lukianov, M; Kuksov, A; Jana, S; Iorsh, I; Izmaylov, R; Shein, K; Gayduchenko, I; Taniguchi, T; Watanabe, K; Novoselov, K S; Goltsman, G N; Principi, A; Bandurin, D A Correlated insulator Moiré bolometer NATURE COMMUNICATIONS, 17 (1), 2026, DOI: 10.1038/s41467-026-76389-4. @article{WOS:001869851900007, title = {Correlated insulator Moiré bolometer}, author = {L Elesin and A L Shilov and M Kravtsov and X Zhou and M Lukianov and A Kuksov and S Jana and I Iorsh and R Izmaylov and K Shein and I Gayduchenko and T Taniguchi and K Watanabe and K S Novoselov and G N Goltsman and A Principi and D A Bandurin}, doi = {10.1038/s41467-026-76389-4}, times_cited = {0}, year = {2026}, date = {2026-08-01}, journal = {NATURE COMMUNICATIONS}, volume = {17}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Light incident on an insulator is generally not expected to turn it into a metal without invoking intense ultrafast excitation that leads to transient structural transitions. Here we show that magic-angle twisted bilayer graphene tuned to half filling of the moir & eacute; band provides a notable exception to this expectation. We find that weak long-wavelength photons, with energies comparable to the flat-band width, selectively heat the low-heat-capacity electronic subsystem, thereby suppressing the correlated gap. This produces a giant resistance change governed not by a persistent photocarrier population, but by the extreme sensitivity of a many-body correlated gap to weak electronic heating. The resulting photon-driven insulator-to-metal transition produces a broadband low-noise photoresponse with voltage responsivity exceeding millivolts per nW of absorbed power. The mechanism is dual to superconducting hot-electron response: radiation-heated electrons suppress a many-body order, but in reverse the correlated insulator melts into a metal, providing robustness to magnetic fields of several tesla and a sharp insulator-to-metal resistive contrast. Our results establish correlated flat-band systems as a platform for ultrasensitive detection of faint long-wavelength radiation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Light incident on an insulator is generally not expected to turn it into a metal without invoking intense ultrafast excitation that leads to transient structural transitions. Here we show that magic-angle twisted bilayer graphene tuned to half filling of the moir & eacute; band provides a notable exception to this expectation. We find that weak long-wavelength photons, with energies comparable to the flat-band width, selectively heat the low-heat-capacity electronic subsystem, thereby suppressing the correlated gap. This produces a giant resistance change governed not by a persistent photocarrier population, but by the extreme sensitivity of a many-body correlated gap to weak electronic heating. The resulting photon-driven insulator-to-metal transition produces a broadband low-noise photoresponse with voltage responsivity exceeding millivolts per nW of absorbed power. The mechanism is dual to superconducting hot-electron response: radiation-heated electrons suppress a many-body order, but in reverse the correlated insulator melts into a metal, providing robustness to magnetic fields of several tesla and a sharp insulator-to-metal resistive contrast. Our results establish correlated flat-band systems as a platform for ultrasensitive detection of faint long-wavelength radiation.
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Shilov, A L; Elesin, L; Kravtsov, M; Covey, J; Ganichev, S D; Kashchenko, M A; Popova, O; Izmaylov, R; Shein, K; Gayduchenko, I; Zhou, X; Yahniuk, I; Taniguchi, T; Watanabe, K; Berdyugin, A I; Wang, Y; Perebeinos, V; Svintsov, D A; Novoselov, K S; Principi, A; Maslov, D L; Bandurin, D A Interaction-limited conductivity of twisted bilayer graphene revealed by giant terahertz photoresistance NATURE COMMUNICATIONS, 17 (1), 2026, DOI: 10.1038/s41467-026-76554-9. @article{WOS:001874211200016, title = {Interaction-limited conductivity of twisted bilayer graphene revealed by giant terahertz photoresistance}, author = {A L Shilov and L Elesin and M Kravtsov and J Covey and S D Ganichev and M A Kashchenko and O Popova and R Izmaylov and K Shein and I Gayduchenko and X Zhou and I Yahniuk and T Taniguchi and K Watanabe and A I Berdyugin and Y Wang and V Perebeinos and D A Svintsov and K S Novoselov and A Principi and D L Maslov and D A Bandurin}, doi = {10.1038/s41467-026-76554-9}, times_cited = {0}, year = {2026}, date = {2026-08-01}, journal = {NATURE COMMUNICATIONS}, volume = {17}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Identifying the microscopic processes limiting conductivity is essential for understanding correlated quantum materials. In twisted bilayer graphene, metallic resistivity follows rho similar to T-alpha with widely varying alpha, fueling competing interpretations from phonon-limited transport and umklapp scattering to strange metallicity and heavy-fermion renormalization. Here, we use terahertz excitation to selectively heat electrons while keeping the lattice cold, separating electron-electron from electron-phonon contributions to resistivity. We observe a giant terahertz photoresistance - reaching several k Omega - showing that electron-electron scattering remains significant even in regimes previously attributed to phonons, including the linear-in-T resistivity near the magic angle. Away from it, photoresistance coexists with quadratic-in-T resistivity at low carrier densities where umklapp and Baber scattering are kinematically forbidden. We identify the breakdown of Galilean invariance in the Dirac dispersion, enabling inter-valley electron-electron collisions, as a possible origin. Our approach establishes terahertz-driven hot-electron transport as a framework for disentangling scattering mechanisms in low-density quantum materials.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Identifying the microscopic processes limiting conductivity is essential for understanding correlated quantum materials. In twisted bilayer graphene, metallic resistivity follows rho similar to T-alpha with widely varying alpha, fueling competing interpretations from phonon-limited transport and umklapp scattering to strange metallicity and heavy-fermion renormalization. Here, we use terahertz excitation to selectively heat electrons while keeping the lattice cold, separating electron-electron from electron-phonon contributions to resistivity. We observe a giant terahertz photoresistance - reaching several k Omega - showing that electron-electron scattering remains significant even in regimes previously attributed to phonons, including the linear-in-T resistivity near the magic angle. Away from it, photoresistance coexists with quadratic-in-T resistivity at low carrier densities where umklapp and Baber scattering are kinematically forbidden. We identify the breakdown of Galilean invariance in the Dirac dispersion, enabling inter-valley electron-electron collisions, as a possible origin. Our approach establishes terahertz-driven hot-electron transport as a framework for disentangling scattering mechanisms in low-density quantum materials.
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Elesin, Leonid; Shilov, Arthur L; Jana, Subhajit; Mazurenko, Ilya; Pantaleon, Pierre A; Kashchenko, Mikhail; Krivovichev, Nikita; Dremov, Viacheslav; Gayduchenko, Igor; Taniguchi, Takashi; Watanabe, Kenji; Wang, Yibo; Novoselov, Kostya S; Svintsov, Dmitry A; Goltsman, Grigory; Titova, Elena I; Bandurin, Denis A Enhanced Terahertz Thermoelectricity Via Engineered Van Hove Singularities and Nernst Effect in Moiré Superlattices ADVANCED FUNCTIONAL MATERIALS, 36 (50), 2026, DOI: 10.1002/adfm.202528325. @article{WOS:001775895800001, title = {Enhanced Terahertz Thermoelectricity Via Engineered Van Hove Singularities and Nernst Effect in Moiré Superlattices}, author = {Leonid Elesin and Arthur L Shilov and Subhajit Jana and Ilya Mazurenko and Pierre A Pantaleon and Mikhail Kashchenko and Nikita Krivovichev and Viacheslav Dremov and Igor Gayduchenko and Takashi Taniguchi and Kenji Watanabe and Yibo Wang and Kostya S Novoselov and Dmitry A Svintsov and Grigory Goltsman and Elena I Titova and Denis A Bandurin}, doi = {10.1002/adfm.202528325}, times_cited = {1}, issn = {1616-301X}, year = {2026}, date = {2026-06-01}, journal = {ADVANCED FUNCTIONAL MATERIALS}, volume = {36}, number = {50}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Thermoelectric materials, long explored for energy harvesting and thermal sensing, convert heat directly into electrical signals. Extending their application to the terahertz (THz) frequency range opens opportunities for low-noise, bias-free THz detection, yet conventional thermoelectrics lack the sensitivity required for practical devices. Thermoelectric coefficients can be strongly enhanced near van Hove singularities (VHS), though these are usually difficult to access in conventional materials. Here it is shown that moir & eacute; band engineering unlocks these singularities for THz optoelectronics. Using graphene and bilayer graphene/hexagonal boron nitride (hBN) moir & eacute; heterostructures as a model system, a pronounced enhancement of the THz photothermoelectric response is observed when the Fermi level is tuned to band-structure singularities. Applying a relatively small magnetic field further boosts the response through the THz-driven Nernst effect, a transverse thermoelectric current driven by the THz-induced temperature gradient. These results establish moir & eacute; superlattices as a versatile platform for THz thermoelectricity and highlight engineered band structures as a route to high-performance THz optoelectronic devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Thermoelectric materials, long explored for energy harvesting and thermal sensing, convert heat directly into electrical signals. Extending their application to the terahertz (THz) frequency range opens opportunities for low-noise, bias-free THz detection, yet conventional thermoelectrics lack the sensitivity required for practical devices. Thermoelectric coefficients can be strongly enhanced near van Hove singularities (VHS), though these are usually difficult to access in conventional materials. Here it is shown that moir & eacute; band engineering unlocks these singularities for THz optoelectronics. Using graphene and bilayer graphene/hexagonal boron nitride (hBN) moir & eacute; heterostructures as a model system, a pronounced enhancement of the THz photothermoelectric response is observed when the Fermi level is tuned to band-structure singularities. Applying a relatively small magnetic field further boosts the response through the THz-driven Nernst effect, a transverse thermoelectric current driven by the THz-induced temperature gradient. These results establish moir & eacute; superlattices as a versatile platform for THz thermoelectricity and highlight engineered band structures as a route to high-performance THz optoelectronic devices.
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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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2025 |
Kudriashov, A; Hovhannisyan, R A; Zhou, X; Elesin, L; Yashina, L V; Novoselov, K S; Bandurin, D A Reconstructing critical current density in Josephson junctions with phase nonlinearity PHYSICAL REVIEW B, 112 (6), 2025, DOI: 10.1103/lgpj-wy72. @article{WOS:001553737700001, title = {Reconstructing critical current density in Josephson junctions with phase nonlinearity}, author = {A Kudriashov and R A Hovhannisyan and X Zhou and L Elesin and L V Yashina and K S Novoselov and D A Bandurin}, doi = {10.1103/lgpj-wy72}, times_cited = {2}, issn = {2469-9950}, year = {2025}, date = {2025-08-01}, journal = {PHYSICAL REVIEW B}, volume = {112}, number = {6}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {In this Letter, we show that the standard Dynes-Fulton analysis, commonly used to reconstruct the critical current density from interference patterns, breaks down in Josephson junctions with nonlinear phase distributions, leading to nonphysical artifacts. To address this, we developed a simple iterative reconstruction algorithm and validated it both numerically and experimentally using a planar Josephson junction model. Unlike conventional approaches based on the logarithmic Hilbert transform, the proposed method allows for incorporating prior knowledge about the system and addresses the fundamental issue of ambiguity in reconstructing the critical current density from interference patterns.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this Letter, we show that the standard Dynes-Fulton analysis, commonly used to reconstruct the critical current density from interference patterns, breaks down in Josephson junctions with nonlinear phase distributions, leading to nonphysical artifacts. To address this, we developed a simple iterative reconstruction algorithm and validated it both numerically and experimentally using a planar Josephson junction model. Unlike conventional approaches based on the logarithmic Hilbert transform, the proposed method allows for incorporating prior knowledge about the system and addresses the fundamental issue of ambiguity in reconstructing the critical current density from interference patterns.
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