Dr Siddharth Dhomkar

	Postdoctoral Research Associate tel: +44 (0)20 7679 2367; ext: 32367 email: jjl.morton@UCL  office: 2C5

 

Research Interests

I am interested in studying atom-like defect centers and associated spins in wide band-gap materials for applications ranging from quantum information science to nano-scale metrology.

In the past, I have investigated Aharanov-Bohm effect and magneto-optic Kerr effect related to epitaxially grown quantum dots & isoelectronic centers and have also explored possibility of using these structures for fabricating solar cells and lasers. 

More recently, I studied charge and spin dynamics associated with various defect centers in diamond for a variety of applications including long-term memory storage, spintronics, nanoscale sensing, and nuclear hyperpolarization.  

At UCL, I am working on a combined atomic force microscope and confocal fluorescence microscope that can work at cryogenic temperatures as low as 1.8 K. This tool is designed to characterize and coherently control spins in a range of materials, down to the single spin level. 

Interesting fact

I am an ardent food lover and an aspiring multi-cuisine chef. Want to own a restaurant one day called "Pune to London via New York!"

Publications

• H. Jayakumar, S. Dhomkar, J. Henshaw, and C. A. Meriles, Spin readout via spin-to-charge conversion in bulk diamond nitrogen-vacancy ensembles, Applied Physics Letters 113, 122404 (2018).
• S. Dhomkar, H. Jayakumar, P. R. Zangara, C. A. Meriles, Charge dynamics in near-surface, variable-density ensembles of nitrogen vacancy centers in diamond, Nano Letters 18, 4046 (2018).
• A. Ajoy, K. Liu, R. Nazaryan, X. Lv, P.R. Zangara, B. Safvati, G. Wang, D. Arnold, G. Li, A. Lin, P. Raghavan, E. Druga, S. Dhomkar, D. Pagliero, J. A. Reimer, D. Suter, C. A. Meriles, A. Pines, Orientation independent room-temperature optical ¹³C hyperpolarization in powdered diamond, Science Advances 4, eaar5492 (2018).
• S. Dhomkar, P. R. Zangara, J. Henshaw, C. A. Meriles, On-Demand Generation of Neutral and Negatively-Charged Silicon-Vacancy Centers in Diamond, Physical Review Letters 120, 117401 (2018).
• D. Pagliero, K. R. K. Rao, P. R. Zangara, S. Dhomkar, H. H. Wong, A. Abril, N. Aslam, A. Parker, J. King, C. E. Avalos, A. Ajoy, J. Wrachtrup, A. Pines, C. A. Meriles, Multispin-assisted optical pumping of bulk ¹³C nuclear spin polarization in diamond, Physical Review B 97, 024422 (2018).
• I. L. Kuskovsky, L. G. Murokh, B. Roy, H. Ji, S. Dhomkar, J. Ludwig, D. Smirnov, M. C. Tamargo, Decoherence in semiconductor nanostructures with type-II band alignment: All-optical measurements using Aharonov-Bohm excitons, Physical Review B 95, 165445 (2017).
• V. Deligiannakis, S. Dhomkar, H. Ji, D. Pagliero, I. L. Kuskovsky, C. A. Meriles, M. C. Tamargo, Spin dynamics of ZnSe-ZnTe nanostructures grown by migration enhanced molecular beam epitaxy, Journal of Applied Physics 121, 115702 (2017).
• S. Dhomkar, J. Henshaw, H. Jayakumar, C. A. Meriles, Long-term data storage in diamond, Science Advances 2, e1600911 (2016).
• H. Jayakumar, J. Henshaw, S. Dhomkar, D. Pagliero, A. Laraoui, N. B. Manson, R. Albu, M. W. Doherty, C. A. Meriles, Optical patterning of trapped charge in nitrogen-doped diamond, Nature Communications 7, 12660 (2016).
• H. Ji, S. Dhomkar, R. Wu, V. Shuvayev, V. Deligiannakis, M. C. Tamargo, J. Ludwig, Z. Lu, D. Smirnov, A. Wang, I. L. Kuskovsky, Optical Anisotropy in Type-II ZnTe/ZnSe Submonolayer Quantum Dots, Journal of Applied Physics 119, 224306 (2016).
• S. Dhomkar, N. Vaxelaire, H. Ji, V. Shuvayev, M. C. Tamargo, I. L. Kuskovsky, I. C. Noyan, Determination of shape anisotropy in embedded low contrast submonolayer quantum dot structures, Applied Physics Letters 107, 251905 (2015).
• S. Dhomkar, H. Ji, B. Roy, V. Deligiannakis, A. Wang, M. C. Tamargo, I. L. Kuskovsky, Measurement and control of size and density of type-II ZnTe/ZnSe submonolayer quantum dots, Journal of Crystal Growth 422, 8 (2015).
• H. Ji, S. Dhomkar, B. Roy, V. Shuvayev, V. Deligiannakis, M. C. Tamargo, J. Ludwig, D. Smirnov, A. Wang, I. L. Kuskovsky, Determination of lateral size distribution of type-II ZnTe/ZnSe stacked submonolayer quantum dots via spectral analysis of optical signature of the Aharanov-Bohm excitons, Journal of Applied Physics 116, 164308 (2014).
• B. Roy, H. Ji, S. Dhomkar, M. C. Tamargo, I. L. Kuskovsky, Observation of oscillations in energy of Aharonov-Bohm excitons in type-II ZnTe/ZnSe stacked submonolayer quantum dots. Physica Status Solidi C 7-8, 1248 (2014).
• S. Dhomkar, U. Manna, I. C. Noyan, M. C. Tamargo, I. L. Kuskovsky, Vertical correlation and miniband formation in submonolayer Zn(Cd)Te/ZnCdSe type-II quantum dots for intermediate band solar cell application, Applied Physics Letters 103, 181905 (2013).
• S. Dhomkar, U. Manna, L. Peng, R. Moug, I. C. Noyan, M. C. Tamargo, I. L. Kuskovsky, Feasibility of submonolayer ZnTe/ZnCdSe quantum dots as intermediate band solar cell material system, Solar Energy Materials & Solar Cells 117, 604 (2013).
• S. Dhomkar, I. L. Kuskovsky, U. Manna, I. C. Noyan, M. C. Tamargo, Optimization of growth conditions of type-II Zn(Cd)Te/ZnCdSe submonolayer quantum dot superlattices for intermediate band solar cells, Journal of Vacuum Science & Technology B 31, 03C119 (2013).
• J. De Jesus, T. A. Garcia, S. Dhomkar, A. Ravikumar, C. Gmachl, G. Chen, A. Shen, D. Ferizovic, M. Muñoz, M. C. Tamargo, Characterization of the three-well active region of a quantum cascade laser using contactless electroreflectance, Journal of Vacuum Science & Technology B 31, 03C134 (2013).
• H. Ji, B. Roy, S. Dhomkar, R. T. Moug, M. C. Tamargo, A. Wang, I. L. Kuskovsky, Tuning Between Quantum-Dot- and Quantum-Well-Like Behaviors in Type II ZnTe Submonolayer Quantum Dots by Controlling Tellurium Flux during MBE Growth, Journal of Electronic Materials 42, 3297 (2013).
• B. Roy, H. Ji, S. Dhomkar, F. J. Cadieu, L. Peng, R. Moug, M. C. Tamargo, I. L. Kuskovsky, Distinguishability of stacks in ZnTe/ZnSe quantum dots via spectral analysis of Aharonov-Bohm oscillations, European Physical Journal B 86, 31 (2013).
• B. Roy, H. Ji, S. Dhomkar, F. J. Cadieu, L. Peng, R. Moug, M. C. Tamargo, Y. Kim, D. Smirnov, I. L. Kuskovsky, Enhancement and narrowing of the Aharonov-Bohm oscillations due to built-in electric field in stacked type-II ZnTe/ZnSe quantum dots: Spectral analysis, Physical Review B 86, 165310 (2012).
• B. Roy, H. Ji, S. Dhomkar, F. J. Cadieu, L. Peng, R. Moug, M. C. Tamargo, I. L. Kuskovsky, Determination of excitonic size with sub-nanometer precision via excitonic Aharonov-Bohm effect in type-II quantum dots, Applied Physics Letters 100, 213114 (2012).
• U. Manna, Q. Zhang, S. Dhomkar, I. F. Salakhutdinov, M. C. Tamargo, I. C. Noyan, G. F. Neumark, I. L. Kuskovsky, Radiative transitions in vertically correlated type-II ZnMgTe/ZnSe multilayer quantum dot structure, Journal of Applied Physics 112, 063521 (2012).