Ashutosh Kumar

@universite-paris-saclay.fr

Postdoctoral Researcher
University of Paris Saclay France



                    

https://researchid.co/science.ashutosh

EDUCATION

Ph.D. in Experimental Condensed Matter Physics

RESEARCH, TEACHING, or OTHER INTERESTS

Condensed Matter Physics, Materials Science, Electronic, Optical and Magnetic Materials, Ceramics and Composites

72

Scopus Publications

539

Scholar Citations

15

Scholar h-index

19

Scholar i10-index

Scopus Publications

  • Effect of crystal field engineering and Fermi level optimization on thermoelectric properties of Ge1.01Te: Experimental investigation and theoretical insight
    Ashutosh Kumar, Preeti Bhumla, Duraisamy Sivaprahasam, Saswata Bhattacharya, and Nita Dragoe
    American Physical Society (APS)
    This study shows a method of enhancing the thermoelectric properties of GeTe-based materials by Ti and Bi co-doping on cation sites along with self-doping with Ge via simultaneous optimization of electronic (via crystal field engineering, and precise Fermi level optimization) and thermal (via point-defect scattering) transport properties. The pristine GeTe possesses high carrier concentration ($n$) due to intrinsic Ge vacancies, low Seebeck coefficient ($\\alpha$), and high thermal conductivity ($\\kappa$). The Ge vacancy optimization and crystal field engineering results in an enhanced $\\alpha$ via excess Ge and Ti doping, which is further improved by band structure engineering through Bi doping. As a result of improved $\\alpha$ and optimized Fermi level (carrier concentration), an enhanced power factor ($\\alpha^2\\sigma$) is obtained for Ti--Bi co-doped Ge$_{1.01}$Te. These experimental results are also evidenced by theoretical calculations of band structure, and thermoelectric parameters using density functional theory and Boltztrap calculations, respectively. A significant reduction in the phonon thermal conductivity ($\\kappa_{ph}$) from $\\sim$ 3.5 W.m$^{-1}$.K$^{-1}$ to $\\sim$ 1.06 W.m$^{-1}$.K$^{-1}$ at 300\\,K for Ti--Bi co-doping in GeTe, attributed to point-defect scattering due to mass and strain field fluctuation, in line with the Debye-Callaway model. The phonon dispersion calculations show a decreasing group velocity in Ti--Bi co-doped GeTe, supporting the obtained reduced $\\kappa_{ph}$. The strategies used in the present study can significantly increase the effective mass, optimize the carrier concentration, and decrease phonon thermal conductivity while achieving an impressive maximum zT value of 1.75 at 773\\,K and average zT (zT$_{av}$) of 1.03 for Ge$_{0.91}$Ti$_{0.02}$Bi$_{0.08}$Te over a temperature range of 300-773\\,K.

  • Magnetic and electrical properties of high-entropy rare-earth manganites
    Ashutosh Kumar, David Bérardan, Diana Dragoe, Eric Riviere, Tomohiro Takayama, Hidenori Takagi, and Nita Dragoe
    Elsevier BV

  • Thermoelectric properties of high-entropy rare-earth cobaltates
    Ashutosh Kumar, Diana Dragoe, David Berardan, and Nita Dragoe
    Elsevier BV

  • Synergistic Effect of Work Function and Acoustic Impedance Mismatch for Improved Thermoelectric Performance in GeTe-WC Composite
    Ashutosh Kumar, Preeti Bhumla, Artur Kosonowski, Karol Wolski, Szczepan Zapotoczny, Saswata Bhattacharya, and Krzysztof T. Wojciechowski
    American Chemical Society (ACS)
    The preparation of composite materials is a promising methodology for concurrent optimization of electrical and thermal transport properties for improved thermoelectric (TE) performance. This study demonstrates how the acoustic impedance mismatch (AIM) and the work function of components decouple the TE parameters to achieve enhanced TE performance of the (1-z)Ge0.87Mn0.05Sb0.08Te-(z)WC composite. The simultaneous increase in the electrical conductivity (σ) and Seebeck coefficient (α) with WC (tungsten carbide) volume fraction (z) results in an enhanced power factor (α2σ) in the composite. The rise in σ is attributed to the creation of favorable current paths through the WC phase located between grains of Ge0.87Mn0.05Sb0.08Te, which leads to increased carrier mobility in the composite. Detailed analysis of the obtained electrical properties was performed via Kelvin probe force microscopy (work function measurement) and atomic force microscopy techniques (spatial current distribution map and current–voltage (I–V) characteristics), which are further supported by density functional theory (DFT) calculations. Furthermore, the difference in elastic properties (i.e., sound velocity) between Ge0.87Mn0.05Sb0.08Te and WC results in a high AIM, and hence, a large interface thermal resistance (Rint) between the phases is achieved. The correlation between Rint and the Kapitza radius depicts a reduced phonon thermal conductivity (κph) of the composite, which is explained using the Bruggeman asymmetrical model. Moreover, the decrease in κph is further validated by phonon dispersion calculations that indicate the decrease in phonon group velocity in the composite. The simultaneous effect of enhanced α2σ and reduced κph results in a maximum figure of merit (zT) of 1.93 at 773 K for (1-z)Ge0.87Mn0.05Sb0.08Te-(z)WC composite for z = 0.010. It results in an average thermoelectric figure of merit (zTav) of 1.02 for a temperature difference (ΔT) of 473 K. This study shows promise to achieve higher zTav across a wide range of composite materials.


  • Developing a novel exenatide-based incretin mimic (αB-Ex): Expression, purification and structural-functional characterization
    Mohammad Mehdi Ghanbarnezhad, Mohammad Bagher Shahsavani, Pramod S. Mali, Mansi Upadhyay, Ashutosh Kumar, Rawayh Muslim Albaghlani, Ali Niazi, and Reza Yousefi
    Elsevier BV

  • Origin of electrical contact resistance and its dominating effect on electrical conductivity in PbTe/CoSb<inf>3</inf> composite
    Artur Kosonowski, Ashutosh Kumar, Karol Wolski, Szczepan Zapotoczny, and Krzysztof T. Wojciechowski
    Elsevier BV

  • A novel strategy for production of liraglutide precursor peptide and development of a new long-acting incretin mimic
    Samaneh Ahmadi, Mohammad Bagher Shahsavani, Zohreh Tavaf, Rawayh Muslim Albaghlany, Ashutosh Kumar, Ali Akbar Moosavi-Movahedi, and Reza Yousefi
    Public Library of Science (PLoS)
    Nowadays, a small number of incretin mimics are used to treat type 2 diabetes mellitus (T2DM) due to their longer half-life. The present study aimed to introduce a novel method for producing the liraglutide precursor peptide (LPP) and developing a potentially new incretin mimic. Here, human αB-crystallin (αB-Cry) was ligated to the LPP at the gene level, and the gene construct was expressed in Escherichia coli with a relatively good efficiency. The hybrid protein (αB-lir) was then purified by a precipitation method followed by anion exchange chromatography. After that, the peptide was released from the carrier protein by a chemical cleavage method yielding about 70%. The LPP was then purified by gel filtration chromatography, and HPLC estimated its purity to be about 98%. Also, the molecular mass of the purified peptide was finally confirmed by mass spectroscopy analysis. Assessment of the secondary structures suggested a dominant α-helical structure for the LPP and a β-sheet rich structure for the hybrid protein. The subcutaneous injection of the LPP and the αB-lir hybrid protein significantly reduced the blood sugar levels in healthy and diabetic mice and stimulated insulin secretion. Also, the hybrid protein exerts its bioactivities more effectively than the LPP over a relatively longer period of time. The results of this study suggested a novel method for the easy and cost-effective production of the LPP and introduced a new long-acting incretin mimic that can be potentially used for the treatment of T2DM patients.

  • A novel method for the chaperone aided and efficient production of human proinsulin in the prokaryotic system
    Fatemeh Khosravi, Mansi Upadhyay, Ashutosh Kumar, Mohammad Bagher Shahsavani, Mohsen Akbarian, Haniyeh Najafi, Ali Mohammad Tamaddon, and Reza Yousefi
    Elsevier BV

  • Role of nutraceuticals in metabolic syndrome
    Brahmeshwar Mishra, Mansi Upadhyay, and Ashutosh Kumar
    Elsevier


  • Charge transport and resistive switching in a 2D hybrid interface
    Karuna Kumari, Ashutosh Kumar, Ajay D Thakur, and S.J. Ray
    Elsevier BV

  • Engineering Electronic Structure and Lattice Dynamics to Achieve Enhanced Thermoelectric Performance of Mn-Sb Co-Doped GeTe
    Ashutosh Kumar, Preeti Bhumla, Taras Parashchuk, Stanislaw Baran, Saswata Bhattacharya, and Krzysztof T. Wojciechowski
    American Chemical Society (ACS)
    GeTe, as a p-type semiconductor, has been intensively studied in recent years as a promising lead-free mid-temperature-range thermoelectric (TE) material. Herein, we report an improved energy conve...

  • Benzimidazole-based fluorophores for the detection of amyloid fibrils with higher sensitivity than Thioflavin-T
    Narayanaperumal Pravin, Rakesh Kumar, Shalini Tripathi, Pardeep Kumar, Ganesh M Mohite, Ambuja Navalkar, Rajlaxmi Panigrahi, Namrata Singh, Laxmikant G. Gadhe, Shaffi Manchanda,et al.
    Wiley
    Protein aggregation into amyloid fibrils is a key feature of a multitude of neurodegenerative diseases such as Alzheimer's, Parkinson's, and Prion disease. To detect amyloid fibrils, fluorophores with high sensitivity and better efficiency coupled with the low toxicity are in high demand even to date. In this pursuit, we have unveiled two benzimidazole‐based fluorescence sensors ([C15H15N3] (C1) and [C16H16N3O2] (C2), which possess exceptional affinity toward different amyloid fibrils in its submicromolar concentration (8 × 10–9 M), whereas under a similar concentration, the gold standard Thioflavin‐T (ThT) fails to bind with amyloid fibrils. These fluorescent markers bind to α‐Syn amyloid fibrils as well as amyloid fibrils forming other proteins/peptides including Aβ42 amyloid fibrils. The 1H‐15N heteronuclear quantum correlation spectroscopy nuclear magnetic resonance data collected on wild‐type α‐Syn monomer with and without the fluorophores (C1 and C2) reveal that there is weak or no interactions between C1 or C2 with residues in α‐Syn monomer, which indirectly reflects the specific binding ability of C1 and C2 to the α‐Syn amyloid fibrils. Detailed studies further suggest that C1 and C2 can detect/bind with the α‐Syn amyloid fibril as low as 100 × 10–9 M. Extremely low or no cytotoxicity is observed for C1 and C2 and they do not interfere with α‐Syn fibrillation kinetics, unlike ThT. Both C1/C2 not only shows selective binding with amyloid fibrils forming various proteins/peptides but also displays excellent affinity and selectivity toward α‐Syn amyloid aggregates in SH‐SY5Y cells and Aβ42 amyloid plaques in animal brain tissues. Overall, our data show that the developed dyes could be used for the detection of amyloid fibrils including α‐Syn and Aβ42 amyloids with higher sensitivity as compared to currently used ThT.

  • Colossal seebeck coefficient in Aurivillius phase-perovskite oxide composite
    Ashutosh Kumar, D. Sivaprahasam, and Ajay D. Thakur
    Elsevier BV

  • Thermal conductivity of PbTe-CoSb<inf>3</inf>bulk polycrystalline composite: role of microstructure and interface thermal resistance
    Artur Kosonowski, Ashutosh Kumar, Taras Parashchuk, Raul Cardoso-Gil, and Krzysztof T. Wojciechowski
    Royal Society of Chemistry (RSC)
    The influence of grain size and interface thermal resistance on thermal conductivity of PbTe–CoSb3 polycrystalline composite.


  • Bi<inf>2</inf>Se<inf>3</inf>-PVDF composite: A flexible thermoelectric system
    Ashutosh Kumar, Ravi Kumar, and Dillip K. Satapathy
    Elsevier BV

  • α-Synuclein aggregation nucleates through liquid–liquid phase separation
    Soumik Ray, Nitu Singh, Rakesh Kumar, Komal Patel, Satyaprakash Pandey, Debalina Datta, Jaladhar Mahato, Rajlaxmi Panigrahi, Ambuja Navalkar, Surabhi Mehra,et al.
    Springer Science and Business Media LLC

  • Graphene mediated resistive switching and thermoelectric behavior in lanthanum cobaltate
    Ashutosh Kumar, Karuna Kumari, S. J. Ray, and Ajay D. Thakur
    AIP Publishing
    Multifunctional materials are of utmost importance owing to the combination of several functionalities into a single device. We present the multifunctional properties, namely, thermoelectric (TE) for energy harvesting and resistive switching (RS) for memory storage in the LaCoO 3 (LCO)–graphene nanocomposite system. The existence of individual phases of LCO and graphene is confirmed from x-ray diffraction and electron microscopy techniques. The x-ray photoelectron spectroscopy measurement reveals the formation of oxygen vacancies in the nanocomposite with the addition of graphene. The bipolar resistive switching behavior observed in a LCO–graphene nanocomposite is explained using space charge limited conduction mechanism and is found to evolve from a trap-limited to a trap-free region with an increase in the graphene volume fraction, which eventually ascribed to the ordering of oxygen vacancies in the nanocomposite system. The endurance plot of the nanocomposite shows a stable RS behavior for consecutive 1000 cycles. On the other hand, the creation of oxygen vacancies in the nanocomposite leads to change in the configurational entropy of charge states of cobalt, which tunes the Seebeck coefficient ( α). The decrease in α leads to an increase in the hopping hole concentration ( n h) estimated using the classical Heikes formula and is consistent with the increase in the electrical conductivity. The increase in oxygen vacancies leads to point-defect scattering, which further reduces the thermal conductivity of the nanocomposite. The optimized TE parameters show a figure-of-merit of 0.004 ± 0.000 48 at 300 K. The simultaneous observation of RS and TE properties in LCO–graphene nanocomposite provides new directions for multifunctional materials.



  • Magnetic and thermoelectric properties of α-MnO<inf>2</inf>nanorods
    Ashutosh Kumar, Karuna Kumari, C. V. Tomy, and Ajay D. Thakur
    AIP Publishing

  • Structural and resistive switching behaviour in lanthanum strontium manganite - Reduced graphene oxide nanocomposite system
    Karuna Kumari, Ashutosh Kumar, Dinesh K. Kotnees, Jayakumar Balakrishnan, Ajay D. Thakur, and S.J. Ray
    Elsevier BV

  • Thermal conductivity of nanostructured Fe<inf>0.04</inf>Co<inf>0.96</inf>Sb<inf>3</inf> skutterudite
    D. Sivaprahasam, S.B. Chandrasekhar, S. Kashyap, Ashutosh Kumar, and R. Gopalan
    Elsevier BV

RECENT SCHOLAR PUBLICATIONS

  • Nonlinearity and Domain Switching in a 3D‐Printed Architected Ferroelectric
    A Pramanick, C Babori, F Albertini, FH Gjrup, AB Oudot, A Kumar, ...
    Advanced Engineering Materials, 2402104 2025

  • Tuning functional properties of 3-D printed ferroelectric ceramics using different architectures
    A Pramanick, C Babori, F Albertini, F Holm Gjrup, A Kumar, M Jrgensen, ...
    Available at SSRN 5001920 2024

  • Structural and Thermoelectric Properties of AlFeMB (M=Ag, Ni, Sb, Ga, and Ge) Intermetallic Borides
    D Sivaprahasam, R Preyadarshini, A Kumar
    arXiv preprint arXiv:2410.12314 2024

  • Boosting Thermoelectric Performance in Nanocrystalline Ternary Skutterudite Thin Films through Metallic CoTe2 Integration
    B Jarwal, S Abbas, TL Chou, SM Vailyaveettil, A Kumar, S Quadir, TT Ho, ...
    ACS Applied Materials & Interfaces 16 (12), 14770-14780 2024

  • Thermoelectric Properties of High‐Entropy Wolframite Oxide: (CoCuNiFeZn)1−xGaxWO4
    A Kumar, A Moll, MN Mouhamadsiradjoudine, F Brisset, D Berardan, ...
    physica status solidi (RRL)–Rapid Research Letters 18 (3), 2300372 2024

  • The concept of the composite thermoelectric materials with attuned electronic structure and mismatched phonon structure (AES-MPS)
    K Wojciechowski, A Kosonowski, A Kumar, T Parashchuk, A Lis, ...
    Thermoelectrics 2023

  • Effect of crystal field engineering and Fermi level optimization on thermoelectric properties of : Experimental investigation and theoretical insight
    A Kumar, P Bhumla, D Sivaprahasam, S Bhattacharya, N Dragoe
    Physical Review Materials 7 (4), 045402 2023

  • Magnetic and electrical properties of high-entropy rare-earth manganites
    A Kumar, D Brardan, D Dragoe, E Riviere, T Takayama, H Takagi, ...
    Materials Today Physics 32, 101026 2023

  • Novel entropy-stabilized fluorite oxides with multifunctional properties
    A Kumar, D Brardan, F Brisset, D Dragoe, N Dragoe
    Journal of Materials Chemistry A 11 (26), 14320-14332 2023

  • Thermoelectric properties of high-entropy rare-earth cobaltates
    A Kumar, D Dragoe, D Berardan, N Dragoe
    Journal of Materiomics 9 (1), 191-196 2023

  • Thermoelectric properties of Sb doped AlFeB
    D Sivaprahasam, A Kumar, B Jayachandran, R Gopalan
    arXiv preprint arXiv:2212.01193 2022

  • Synergistic effect of work function and acoustic impedance mismatch for improved thermoelectric performance in GeTe-WC composite
    A Kumar, P Bhumla, A Kosonowski, K Wolski, S Zapotoczny, ...
    ACS Applied Materials & Interfaces 14 (39), 44527-44538 2022

  • Effect of interface thermal resistance on thermoelectric properties of acoustically mismatched composite
    A Kumar, KT Wojciechowski
    Journal of the European Ceramic Society 42 (10), 4227-4232 2022

  • Decoupled atomic contribution boosted high thermoelectric performance in mixed cation spinel oxides ACo2O4
    A Srivastava, M Mukherjee, AK Singh
    Applied Physics Letters 120 (24) 2022

  • Origin of electrical contact resistance and its dominating effect on electrical conductivity in PbTe/CoSb3 composite
    A Kosonowski, A Kumar, K Wolski, S Zapotoczny, KT Wojciechowski
    Journal of the European Ceramic Society 42 (6), 2844-2852 2022

  • Improved thermoelectric properties in (1-x) LaCoO3/(x) La0. 7Sr0. 3CoO3 composite
    A Kumar, D Sivaprahasam, AD Thakur
    Materials Chemistry and Physics 269, 124750 2021

  • Electrical and Thermal transport studies of Sr and Mn co-substituted NdCoO3
    A Kumar
    arXiv preprint arXiv:2107.10564 2021

  • Charge transport and resistive switching in a 2D hybrid interface
    K Kumari, A Kumar, AD Thakur, SJ Ray
    Materials Research Bulletin 139, 111195 2021

  • Engineering electronic structure and lattice dynamics to achieve enhanced thermoelectric performance of Mn–Sb Co-doped GeTe
    A Kumar, P Bhumla, T Parashchuk, S Baran, S Bhattacharya, ...
    Chemistry of Materials 33 (10), 3611-3620 2021

  • Colossal Seebeck coefficient in Aurivillius phase-perovskite oxide composite
    A Kumar, D Sivaprahasam, AD Thakur
    Journal of Alloys and Compounds 853, 157001 2021

MOST CITED SCHOLAR PUBLICATIONS

  • Graphene mediated resistive switching and thermoelectric behavior in lanthanum cobaltate
    A Kumar, K Kumari, SJ Ray, AD Thakur
    Journal of Applied Physics 127 (23) 2020
    Citations: 46

  • Thermoelectric properties of high-entropy rare-earth cobaltates
    A Kumar, D Dragoe, D Berardan, N Dragoe
    Journal of Materiomics 9 (1), 191-196 2023
    Citations: 41

  • Engineering electronic structure and lattice dynamics to achieve enhanced thermoelectric performance of Mn–Sb Co-doped GeTe
    A Kumar, P Bhumla, T Parashchuk, S Baran, S Bhattacharya, ...
    Chemistry of Materials 33 (10), 3611-3620 2021
    Citations: 40

  • Improvement of thermoelectric properties of lanthanum cobaltate by Sr and Mn co-substitution
    A Kumar, D Sivaprahsam, AD Thakur
    Journal of Alloys and Compounds 735, 1787-1791 2018
    Citations: 37

  • Structural and resistive switching behaviour in lanthanum strontium manganite-Reduced graphene oxide nanocomposite system
    K Kumari, A Kumar, DK Kotnees, J Balakrishnan, AD Thakur, SJ Ray
    Journal of Alloys and Compounds 815, 152213 2020
    Citations: 34

  • Thermoelectric properties of (1-x) LaCoO3. xLa0. 7Sr0. 3MnO3 composite
    A Kumar, K Kumari, B Jayachandran, D Sivaprahasam, AD Thakur
    Journal of Alloys and Compounds 749, 1092-1097 2018
    Citations: 32

  • Bi2Se3-PVDF composite: A flexible thermoelectric system
    A Kumar, R Kumar, DK Satapathy
    Physica B: Condensed Matter 593, 412275 2020
    Citations: 28

  • Magnetic and electrical properties of high-entropy rare-earth manganites
    A Kumar, D Brardan, D Dragoe, E Riviere, T Takayama, H Takagi, ...
    Materials Today Physics 32, 101026 2023
    Citations: 24

  • Charge transport and resistive switching in a 2D hybrid interface
    K Kumari, A Kumar, AD Thakur, SJ Ray
    Materials Research Bulletin 139, 111195 2021
    Citations: 23

  • Charge transport mechanism and thermoelectric behavior in Te:(PEDOT: PSS) polymer composites
    A Kumar, M Battabyal, A Chauhan, G Suresh, R Gopalan, DK Satapathy
    Materials Research Express 6 (11), 115302 2019
    Citations: 23

  • Thermoelectric Properties of (1− x) LaCoO3.(x) La0. 95Sr0. 05CoO3 composite
    A Kumar, K Kumari, B Jayachandran, D Sivaprahasam, AD Thakur
    Materials Research Express 6 (5), 055502 2019
    Citations: 22

  • Effective thermal conductivity of SrBi4Ti4O15-La0. 7Sr0. 3MnO3 oxide composite: Role of particle size and interface thermal resistance
    A Kumar, A Kosonowski, P Wyzga, KT Wojciechowski
    Journal of the European Ceramic Society 41 (1), 451-458 2021
    Citations: 21

  • Synergistic effect of work function and acoustic impedance mismatch for improved thermoelectric performance in GeTe-WC composite
    A Kumar, P Bhumla, A Kosonowski, K Wolski, S Zapotoczny, ...
    ACS Applied Materials & Interfaces 14 (39), 44527-44538 2022
    Citations: 20

  • Thermal conductivity of nanostructured Fe0. 04Co0. 96Sb3 skutterudite
    D Sivaprahasam, SB Chandrasekhar, S Kashyap, A Kumar, R Gopalan
    Materials Letters 252, 231-234 2019
    Citations: 17

  • Magnetothermopower, magnetoresistance and magnetothermal conductivity in La0. 95Sr0. 05Co1− xMnxO3 (0.00≤ x≤ 1.00)
    A Kumar, CV Tomy, AD Thakur
    Materials Research Express 5 (8), 086110 2018
    Citations: 16

  • Effect of interface thermal resistance on thermoelectric properties of acoustically mismatched composite
    A Kumar, KT Wojciechowski
    Journal of the European Ceramic Society 42 (10), 4227-4232 2022
    Citations: 14

  • Thermal conductivity of PbTe–CoSb 3 bulk polycrystalline composite: role of microstructure and interface thermal resistance
    A Kosonowski, A Kumar, T Parashchuk, R Cardoso-Gil, KT Wojciechowski
    Dalton Transactions 50 (4), 1261-1273 2021
    Citations: 14

  • Decoupled atomic contribution boosted high thermoelectric performance in mixed cation spinel oxides ACo2O4
    A Srivastava, M Mukherjee, AK Singh
    Applied Physics Letters 120 (24) 2022
    Citations: 11

  • Improved thermoelectric properties in (1-x) LaCoO3/(x) La0. 7Sr0. 3CoO3 composite
    A Kumar, D Sivaprahasam, AD Thakur
    Materials Chemistry and Physics 269, 124750 2021
    Citations: 11

  • Novel entropy-stabilized fluorite oxides with multifunctional properties
    A Kumar, D Brardan, F Brisset, D Dragoe, N Dragoe
    Journal of Materials Chemistry A 11 (26), 14320-14332 2023
    Citations: 9