RC
R. Conte
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4 records found
1
Journal article
(2026)
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Serhii Volosheniuk, Riccardo Conte, Eugenia Pyurbeeva, Thomas Baum, Manuel Vilas-Varela, Saleta Fernández, Diego Peña, Herre S.J. van der Zant, Pascal Gehring
Particle-exchange heat engines operate without moving parts or time-dependent driving, relying solely on static energy-selective transport. Here, we realize a particle-exchange quantum heat engine based on a single diradical molecule, which is only a few nanometers in size. We experimentally investigate its operation at low temperatures and demonstrate that both the power output and efficiency are significantly enhanced by Kondo correlations, reaching up to 53% of the Curzon-Ahlborn limit. These results establish molecular-scale particle-exchange engines as promising candidates for low-temperature applications where extreme miniaturization and energy efficiency are paramount.
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Particle-exchange heat engines operate without moving parts or time-dependent driving, relying solely on static energy-selective transport. Here, we realize a particle-exchange quantum heat engine based on a single diradical molecule, which is only a few nanometers in size. We experimentally investigate its operation at low temperatures and demonstrate that both the power output and efficiency are significantly enhanced by Kondo correlations, reaching up to 53% of the Curzon-Ahlborn limit. These results establish molecular-scale particle-exchange engines as promising candidates for low-temperature applications where extreme miniaturization and energy efficiency are paramount.
Competing Charge Transport Pathways
A Spirobifluorene-Based Molecular Loop
Understanding the relationship between molecular structure and charge transport remains a crucial aspect towards integrating single molecules into electronic devices, especially in systems which feature multiple conducting pathways. Here we report the synthesis of a molecular loop that incorporates a rigid 9,9′-spirobifluorene (SBF) core as a central mounting point for thiol anchoring groups and a cycloparaphenylene (CPP) backbone. The model compound is synthesized by a Suzuki–Miyaura coupling between a CPP precursor and a functionalized SBF derivative, followed by reductive aromatization of the macrocycle. The resulting macrocycles are fully characterized and enantiomerically resolved by chiral high-performance liquid chromatography (HPLC), and their chiroptical properties are investigated. Conductance measurements in a mechanically controlled break-junction (MCBJ) setup demonstrate reproducible single-molecule junction formation with two dominant conductance plateaus near 2 × 10−4 G0 and 4 × 10−5 G0, observed across different samples and applied voltages. The observed conductance features are consistent with multiple reproducible junction configurations, highlighting the molecular loop as a promising platform for studying charge transport through multiple intramolecular pathways.
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Understanding the relationship between molecular structure and charge transport remains a crucial aspect towards integrating single molecules into electronic devices, especially in systems which feature multiple conducting pathways. Here we report the synthesis of a molecular loop that incorporates a rigid 9,9′-spirobifluorene (SBF) core as a central mounting point for thiol anchoring groups and a cycloparaphenylene (CPP) backbone. The model compound is synthesized by a Suzuki–Miyaura coupling between a CPP precursor and a functionalized SBF derivative, followed by reductive aromatization of the macrocycle. The resulting macrocycles are fully characterized and enantiomerically resolved by chiral high-performance liquid chromatography (HPLC), and their chiroptical properties are investigated. Conductance measurements in a mechanically controlled break-junction (MCBJ) setup demonstrate reproducible single-molecule junction formation with two dominant conductance plateaus near 2 × 10−4 G0 and 4 × 10−5 G0, observed across different samples and applied voltages. The observed conductance features are consistent with multiple reproducible junction configurations, highlighting the molecular loop as a promising platform for studying charge transport through multiple intramolecular pathways.
Journal article
(2026)
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Riccardo Conte, Lucienne van der Geest, Minu Sheeja, Przemyslaw Gawel, Cina Foroutan-Nejad, Herre S.J. van der Zant
Voltage-driven memristive switching has been reported in molecular junctions, yet its microscopic origin often remains elusive. Here, we study three rigid OPE-like derivatives that lack an obvious internal switching pathway. Using mechanically controlled break junctions (MCBJs), we observe nonvolatile, bistable, hysteretic I–V characteristics at cryogenic temperatures. We introduce a quantitative analysis workflow that classifies memristive I–Vs, clusters the two conductance states, and extracts switching features and stability metrics from repeated measurements at fixed displacement. While all molecules exhibit memristive behavior, stability and hysteresis reproducibility depend strongly on anchoring and connectivity: the linear biphenyl backbone with thiolate (SAc) anchoring shows the most reproducible, predominantly field-driven hysteresis, whereas the meta-phenyl variant with thioether (SMe) anchoring is dominated by stochastic, current-driven events. The resulting conductance statistics point to an extrinsic, mechanically mediated origin involving contact rearrangements, multimolecule transport, blinking (open–closed) contacts, injection-point shifts, and π–π-stacking dimerization.
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Voltage-driven memristive switching has been reported in molecular junctions, yet its microscopic origin often remains elusive. Here, we study three rigid OPE-like derivatives that lack an obvious internal switching pathway. Using mechanically controlled break junctions (MCBJs), we observe nonvolatile, bistable, hysteretic I–V characteristics at cryogenic temperatures. We introduce a quantitative analysis workflow that classifies memristive I–Vs, clusters the two conductance states, and extracts switching features and stability metrics from repeated measurements at fixed displacement. While all molecules exhibit memristive behavior, stability and hysteresis reproducibility depend strongly on anchoring and connectivity: the linear biphenyl backbone with thiolate (SAc) anchoring shows the most reproducible, predominantly field-driven hysteresis, whereas the meta-phenyl variant with thioether (SMe) anchoring is dominated by stochastic, current-driven events. The resulting conductance statistics point to an extrinsic, mechanically mediated origin involving contact rearrangements, multimolecule transport, blinking (open–closed) contacts, injection-point shifts, and π–π-stacking dimerization.
Journal article
(2024)
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Alessandra Canetta, Serhii Volosheniuk, Sayooj Satheesh, José Pedro Alvarinhas Batista, Aloïs Castellano, Riccardo Conte, Daniel George Chica, Herre S.J. van der Zant, Pascal Gehring, More authors...
Heat-to-charge conversion efficiency of thermoelectric materials is closely linked to the entropy per charge carrier. Thus, magnetic materials are promising building blocks for highly efficient energy harvesters as their carrier entropy is boosted by a spin degree of freedom. In this work, we investigate how this spin-entropy impacts heat-to-charge conversion in the A-type antiferromagnet CrSBr. We perform simultaneous measurements of electrical conductance and thermocurrent while changing magnetic order using the temperature and magnetic field as tuning parameters. We find a strong enhancement of the thermoelectric power factor at around the Néel temperature. We further reveal that the power factor at low temperatures can be increased by up to 600% upon applying a magnetic field. Our results demonstrate that the thermoelectric properties of 2D magnets can be optimized by exploiting the sizable impact of spin-entropy and confirm thermoelectric measurements as a sensitive tool to investigate subtle magnetic phase transitions in low-dimensional magnets.
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Heat-to-charge conversion efficiency of thermoelectric materials is closely linked to the entropy per charge carrier. Thus, magnetic materials are promising building blocks for highly efficient energy harvesters as their carrier entropy is boosted by a spin degree of freedom. In this work, we investigate how this spin-entropy impacts heat-to-charge conversion in the A-type antiferromagnet CrSBr. We perform simultaneous measurements of electrical conductance and thermocurrent while changing magnetic order using the temperature and magnetic field as tuning parameters. We find a strong enhancement of the thermoelectric power factor at around the Néel temperature. We further reveal that the power factor at low temperatures can be increased by up to 600% upon applying a magnetic field. Our results demonstrate that the thermoelectric properties of 2D magnets can be optimized by exploiting the sizable impact of spin-entropy and confirm thermoelectric measurements as a sensitive tool to investigate subtle magnetic phase transitions in low-dimensional magnets.