Om Prakash

@vttresearch.com

Research Scientist, Quantum computing hardware, VTT Technical Research Centre of Finland Ltd
VTT Technical Research Centre of Finland Ltd



                    

https://researchid.co/omultphy

RESEARCH INTERESTS

Superconducting materials and devices, condensed matter physics and low temperature physics

18

Scopus Publications

305

Scholar Citations

6

Scholar h-index

5

Scholar i10-index

Scopus Publications

  • Time-reversal symmetry breaking in the superconducting low carrier density quasiskutterudite Lu3 Os4 Ge13
    A. Kataria, J. A. T. Verezhak, O. Prakash, R. K. Kushwaha, A. Thamizhavel, S. Ramakrishnan, M. S. Scheurer, A. D. Hillier, and R. P. Singh
    American Physical Society (APS)

  • Exergy and energy analysis of sensible heat storage based double pass hybrid solar air heater
    Om Prakash, Anil Kumar, Samsher, Kumaresh Dey, and Ankish Aman
    Elsevier BV

  • Dynamic analysis of daylight factor, thermal comfort and energy performance under clear sky conditions for building: An experimental validation
    Asim Ahmad, Om Prakash, Anil Kumar, S.M. Mozammil Hasnain, Puneet Verma, Ali Zare, Gaurav Dwivedi, and Anukul Pandey
    Elsevier BV

  • Thermal performance and energy consumption analysis of retail buildings through daylighting: A numerical model with experimental validation
    Om Prakash, Asim Ahmad, Anil Kumar, S.M. Mozammil Hasnain, Ali Zare, and Puneet Verma
    Elsevier BV

  • Commissioning Process and Energy Analysis in the Building: A Case Study for Ranchi City
    Om Prakash, Bharath Bhushan, Anil Kumar, and Ankish Aman
    Springer Nature Singapore

  • CFD Analysis of an Airfoil Due to the Influence of Active Airflow
    Asim Ahmad, Om Prakash, and Anil Kumar
    Springer Nature Singapore

  • Bamboo as a complementary crop to address climate change and livelihoods – Insights from India
    Arun Kumar Dwivedi, Anil Kumar, Prashant Baredar, and Om Prakash
    Elsevier BV

  • Preface


  • Nodeless superconductivity and the peak effect in the quasiskutterudites Lu3Os4Ge13 and Y3Ru4Ge13
    Z. F. Weng, M. Smidman, G. M. Pang, O. Prakash, Y. Chen, Y. J. Zhang, S. Ramakrishnan, and H. Q. Yuan
    American Physical Society (APS)
    We report an investigation of the superconducting states of $\\mathrm{Lu}_3\\mathrm{Os}_4\\mathrm{Ge}_{13}$ and $\\mathrm{Y}_3\\mathrm{Ru}_4\\mathrm{Ge}_{13}$ single crystals by measurements of the electrical resistivity, ac susceptibility and London penetration depth. The analysis of the penetration depth and the derived superfluid density indicates the presence of nodeless superconductivity and suggest that there are multiple superconducting gaps in both materials. Furthermore, ac susceptibility measurements of both compounds display the peak effect in the low temperature region of the $H-T$ phase diagram. This anomalous increase of the critical current with field gives an indication of a change of the arrangement of flux lines in the mixed state, as found in some of the isostructural stannide materials.

  • Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure
    Om Prakash, Anil Kumar, A. Thamizhavel, and S. Ramakrishnan
    American Association for the Advancement of Science (AAAS)
    Going cold with Bismuth Many elemental metals, such as lead and aluminum, become superconducting at low temperatures. Bismuth, a semimetal with very low carrier density, stays nonsuperconducting down to 10 mK. Prakash et al. performed tricky magnetization measurements to show that pure bulk bismuth does undergo the superconducting transition at a tiny temperature of about 0.5 mK (see the Perspective by Behnia). Because bismuth does not fit neatly into the standard picture of superconductivity, further theoretical work is necessary to explain the findings. Science , this issue p. 52 ; see also p. 26

  • Ferromagnetic ordering of minority Ce3+ spins in a quasi-skutterudite Ce3Os4Ge13 single crystal
    Om Prakash, A. Thamizhavel, and S. Ramakrishnan
    American Physical Society (APS)
    We report site disorder driven ferromagnetic ordering of nearly 8$\\%$ Ce atoms in single crystalline Ce${_3}$Os${_4}$Ge$_{13}$ below 0.5~K. Ce${_3}$Os${_4}$Ge$_{13}$ crystallizes in a cubic structure with space group $\\it{Pm\\bar{3}n}$. The structural analysis shows the presence of site-disorder in the system, where 2(a) Ge site is partially occupied by the Ce atoms. Due to the small Ce $4f$-ligand hybridization, these Ce atoms are in the Ce$^{3+}$ (magnetic) state while rest of the Ce atoms in the unit cell are in Ce$^{4-\\delta}$ (non-magnetic) state. The heat capacity shows a peak below 0.5~K corresponding to the ferromagnetic ordering of the Ce$^{3+}$ moments. The ferromagnetic ordering below 0.5~K is also seen in the ac-susceptibility data. At low temperatures (1.8~K$\\leq T\\leq 6$~K), the magnetization shows $log(T)$ dependence, whereas the resistivity shows power law ($T^n$) temperature dependence indicating the non-Fermi liquid behavior of the quasiparticles.

  • Multiband superconductivity in Lu<inf>3</inf>Os<inf>4</inf>Ge<inf>13</inf>
    Om Prakash, A Thamizhavel, and S Ramakrishnan
    IOP Publishing
    Intermetallic R3T4X13 series consist of a cage-like structure and have attracted attention due to their unconventional electronic ground states. In this work, we report the normal and superconducting state properties of a high-quality single crystal of Lu3Os4Ge13. Lu3Os4Ge13 belongs to the above-mentioned series and crystallizes in a cubic crystal structure with the space group Pm 3 ¯ n . Using electrical transport, magnetization and heat capacity measurements, we show that Lu3Os4Ge13 is a type-II multi-band superconductor (Tc = 3.1 K) with unusual superconducting properties. The analysis of the low-temperature heat capacity data suggests that Lu3Os4Ge13 is a moderately coupled multi-band BCS superconductor with two gaps ( 2 Δ / k B T c = 3.68 ± 0.04 & 0.34 ± 0.02 ) in the superconducting state. The dc-magnetization (M−H) shows a large reversible region in the superconducting state similar to the vortex liquid phase observed in high-Tc superconductors. The value of the Ginzburg number Gi suggests that the thermal fluctuations, though small compared to those in high-Tc cuprates, may play an important role in the unpinning of the vortices in this compound. The electronic band structure calculations show that three bands cross the Fermi level and constitute a complex Fermi surface in Lu3Os4Ge13.

  • Review on global solar drying status


  • Superconductivity in Lu<inf>3</inf>Os<inf>4</inf>Ge<inf>13</inf>
    Om Prakash, A Thamizhavel, and S Ramakrishnan
    IOP Publishing
    We report the normal and superconducting state properties of high quality single crystal of Lu3Os4Ge13 grown by Czochralski method. Lu3Os4Ge13 crystallises in the cubic crystal structure (space group Pm3n) . Lu3Os4Ge13 is a type-II superconductor (Tc = 3.1 K) as determined by the electrical transport, magnetisation and heat capacity measurements. The thermopower measurement shows a large phonon drag effect at low temperatures. The electronic band structure calculations show a multi-valley type band structure and a complex Fermi surface in Lu3Os4Ge13, making it a possible candidate to observe a magnetic field induced triplet superconductivity at ultra-low temperatures.

  • Superconductivity in Y<inf>3</inf>Ru<inf>4</inf>Ge<inf>13</inf> and Lu<inf>3</inf>Os<inf>4</inf>Ge<inf>13</inf>: A comparative study
    Om Prakash, A Thamizhavel, and S Ramakrishnan
    IOP Publishing
    A variety of unconventional superconductors have low carrier density as a common factor. However, the underlying mechanism of superconductivity in such low carrier density systems is not well understood. Besides, small carrier density is an unfavourable component for conventional superconductivity as described by the Bardeen-Cooper-Schrieffer (BCS) theory. Therefore, studying low carrier density systems can lead to a better understanding in such systems. In this paper, we report superconductivity property studies in low carrier density systems, Y3Ru4Ge13 and Lu3Os4Ge13, using various experimental techniques. Single crystals of Y3Ru4Ge13 and Lu3Os4Ge13 have been grown using the Czochralski crystal pulling method in a tetra-arc furnace. The x-ray diffraction experiment reveals that both compounds crystallize in cubic structure (space group Pm3n, no. 223). The transport, magnetization and heat capacity measurements show that Y3Ru4Ge13 single crystal undergoes a superconducting transition at 2.85 K, whereas, Lu3Os4Ge13 becomes superconductor at 3.1 K.


  • Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at μk temperatures
    Anil Kumar, Om Prakash, and S. Ramakrishanan
    AIP Publishing LLC
    A special sample measurement chamber has been developed to perform experiments at ultralow temperatures and ultralow magnetic field. A high permeability material known as cryoperm 10 and Pb is used to shield the measurement space consisting of the signal detecting set-up and the sample. The detecting setup consists of a very sensitive susceptibility coil wound on OFHC Cu bobbin.


RECENT SCHOLAR PUBLICATIONS

  • Broken time-reversal symmetry in the cubic skutterudite-like superconductor
    A Kataria, JAT Verezhak, O Prakash, RK Kushwaha, A Thamizhavel, ...
    Physical Review B 108 (21), 214512 2023

  • Fragile electronic superconductivity in a Bi single crystal
    A Kumar, O Prakash, R Loke, A Pramanik, R Sensarma, S Ramakrishnan, ...
    Physical Review B 108 (22), 224512 2023

  • Time-reversal symmetry breaking in the superconducting low carrier density quasiskutterudite
    A Kataria, JAT Verezhak, O Prakash, RK Kushwaha, A Thamizhavel, ...
    Physical Review B 107 (10), L100506 2023

  • Superconductivity in Pt-doped ScPdBi single crystals
    O Prakash, M Klemm, M Aronson
    APS March Meeting Abstracts 2018, F31. 004 2018

  • Discovery of superconductivity in a low carrier density system: Bismuth
    S Ramakrishnan, O Prakash, A Thamizhavel, A Kumar
    APS March Meeting Abstracts 2018, V05. 005 2018

  • Nodeless superconductivity and the peak effect in the quasiskutterudites and
    ZF Weng, M Smidman, GM Pang, O Prakash, Y Chen, YJ Zhang, ...
    Physical Review B 95 (18), 184501 2017

  • Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure
    O Prakash, A Kumar, A Thamizhavel, S Ramakrishnan
    Science 355 (6320), 52-55 2017

  • Ferromagnetic ordering of minority spins in a quasi-skutterudite single crystal
    O Prakash, A Thamizhavel, S Ramakrishnan
    Physical Review B 93 (6), 064427 2016

  • Multiband superconductivity in Lu3Os4Ge13
    O Prakash, A Thamizhavel, S Ramakrishnan
    Superconductor Science and Technology 28 (11), 115012 2015

  • Superconductivity in Lu3Os4Ge13
    O Prakash, A Thamizhavel, S Ramakrishnan
    Journal of Physics: Conference Series 592 (1), 012065 2015

  • Superconductivity in Y3Ru4Ge13 and Lu3Os4Ge13: A comparative study
    O Prakash, A Thamizhavel, S Ramakrishnan
    Journal of Physics: Conference Series 568 (2), 022039 2014

  • Superconductivity in a low carrier density system: A single crystal study of cubic
    O Prakash, A Thamizhavel, AK Nigam, S Ramakrishnan
    AIP Conference Proceedings 1591 (1), 1572-1574 2014

  • Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at K temperatures
    A Kumar, O Prakash, S Ramakrishanan
    Solid State Physics 1591 (1), 644-645 2014

  • Superconductivity in a low carrier density system: A single crystal study of cubic Y3Ru4Ge13
    O Prakash, A Thamizhavel, AK Nigam, S Ramakrishnan
    Physica C: Superconductivity 492, 90-95 2013

MOST CITED SCHOLAR PUBLICATIONS

  • Evidence for bulk superconductivity in pure bismuth single crystals at ambient pressure
    O Prakash, A Kumar, A Thamizhavel, S Ramakrishnan
    Science 355 (6320), 52-55 2017
    Citations: 205

  • Ferromagnetic ordering of minority spins in a quasi-skutterudite single crystal
    O Prakash, A Thamizhavel, S Ramakrishnan
    Physical Review B 93 (6), 064427 2016
    Citations: 36

  • Multiband superconductivity in Lu3Os4Ge13
    O Prakash, A Thamizhavel, S Ramakrishnan
    Superconductor Science and Technology 28 (11), 115012 2015
    Citations: 19

  • Nodeless superconductivity and the peak effect in the quasiskutterudites and
    ZF Weng, M Smidman, GM Pang, O Prakash, Y Chen, YJ Zhang, ...
    Physical Review B 95 (18), 184501 2017
    Citations: 13

  • Superconductivity in a low carrier density system: A single crystal study of cubic Y3Ru4Ge13
    O Prakash, A Thamizhavel, AK Nigam, S Ramakrishnan
    Physica C: Superconductivity 492, 90-95 2013
    Citations: 13

  • Time-reversal symmetry breaking in the superconducting low carrier density quasiskutterudite
    A Kataria, JAT Verezhak, O Prakash, RK Kushwaha, A Thamizhavel, ...
    Physical Review B 107 (10), L100506 2023
    Citations: 7

  • Superconductivity in Lu3Os4Ge13
    O Prakash, A Thamizhavel, S Ramakrishnan
    Journal of Physics: Conference Series 592 (1), 012065 2015
    Citations: 6

  • Broken time-reversal symmetry in the cubic skutterudite-like superconductor
    A Kataria, JAT Verezhak, O Prakash, RK Kushwaha, A Thamizhavel, ...
    Physical Review B 108 (21), 214512 2023
    Citations: 3

  • Superconductivity in Y3Ru4Ge13 and Lu3Os4Ge13: A comparative study
    O Prakash, A Thamizhavel, S Ramakrishnan
    Journal of Physics: Conference Series 568 (2), 022039 2014
    Citations: 2

  • Superconductivity in a low carrier density system: A single crystal study of cubic
    O Prakash, A Thamizhavel, AK Nigam, S Ramakrishnan
    AIP Conference Proceedings 1591 (1), 1572-1574 2014
    Citations: 1