Yashar Komijani

Postdoctoral fellow

Condensed matter physics theroy group

Rutgers University

CV - My detailed CV can be found here.

Google Scholar - my page is here.

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Post doc - Currently, I am a group post doc at the condensed matter theory group in Rutgers university, working with Prof. Piers Coleman and Prof. Natan Andrei. Before coming here, I did a postdoc with Prof. Ian Affleck at University of British Columbia in Vancouver. My current research interests include (multi-channel) Kondo problem, Frustrated magnetism, Majorana fermions and fractional quantum Hall regime.

PhD - During my PhD in the group of Prof. Ensslin (www.nanophys.ethz.ch), I investigated low-temperature hole transport through p-type GaAs quantum point contacts and quantum dots. The interest in p-type GaAs nano-structures arises primarily from the fact that the Coulomb interaction and spin-orbit interaction are strong in these devices, making them especially suitable for investigating many-body e.ffects such as the 0.7 conductance anomaly in quantum point contacts (QPCs).

We used the local anodic oxidation lithography by an atomic force microscope and shallow chemical etching in combination with top-gates in order to de.fine highly tunable nano-structures in two-dimensional hole gases (2DHGs). Our experiments on hole QPCs demonstrated a strong anisotropic modifi.cation of the Land.e g-factor of holes due to the confi.nement. We extracted numerical values for the g-factor of 1D confined holes which agree better with theoretical predictions than previous optical measurements. Furthermore, we employed strong magnetic .fields perpendicular to the plane of the 2DHG in order to exploit localization phenomena which are potentially linked to the 0.7 anomaly. These experiments provided indirect evidence for presence of a quasi-bound state in the QPC and supported the explanation of the 0.7 anomaly based on the Coulomb blockade and the Kondo physics.

On quantum dots, we demonstrated the observation of excited states in a small hole QD and deviations from the constant interaction model. Integration of a QPC in the vicinity of a dot and the capacitive coupling of the two enabled the time-averaged as well as time-resolved charge detection of hole tunneling in the QD. The time resolution provided information about the dense spectrum of the QD. Moreover, we analyzed the statistics of the charge transfer in the framework of full counting statistics (FCS).

My PhD thesis can be found here: pdf

Master - For my master project I worked on the fabrication and analysis of 2D and 3D photonic crystlas. Together with Bahar Khadem-Hosseinieh and advised by Prof. Shahabadi, we managed to apply the scattering theory of quantum mechanics to study the scattering of EM waves from photonic crystals. This was done based on the notion of the photon wavefunction which provided a unified framework according to which the Maxwell equations could be treated on the same footing as the first quantized Dirac equation. For the experimental part of the project perfromed in the Thin Film Lab (www.tfl.ir) of ECE dept. of Univ. of Tehran and under supervision of Prof. Mohajerzadeh, we improved the perforamance of UV assisted chemical etching of PET plastic and fabricated Yablonovite (a 3D photonic crystal) in this material. Moreover, we tried to cultivate the optical properties of carbon nanotubes by growing them along patterned structures to realize basic optical elements.

My Master thesis (in Farsi) can be found here: pdf

Bachelor - For by bachelor project, I worked on improving the performance of TCP protocol over wireless links. Using LBNL ns (network simulator), we compared the performance of diffferent versions of TCP in this context and came up with a new variation of the protocol that improved the throughput of data transfer while maintaining an end-to-end semantic of the connection. This lead to pdf and pdf.

Publications

17. Y. Komijani, P. Coleman, Revisiting the stochastic theory of lineshapes, in preparation.

16. D. Pikulin, Y. Komijani, I. Affleck, Luttinger liquid in contact with a Kramers pair of Majorana bound states, accepted in Phys. Rev. B.

15. Y. Komijani, P. Simon, I. Affleck, Orbital Kondo effect in fractional quantum Hall systems, Phys. Rev. B 92, 075301 (2015). [doi/arXiv]

14. Y. Komijani, I. Affleck, Effect of disorder on the conductance of (non-) topological SN junctions, Journal of Statistical Mechanics, P11017 (2014). [doi/arXiv]

13. Y. Komijani, I. Affleck, Deteting a quantum critical point in topological SN junctions, Phys. Rev. B 90, 115107 (2014). [doi/arXiv]

12. Y. Komijani, R. Yoshii, I. Affleck, Interaction effects in Aharonov-Bohm-Kondo rings, Phys. Rev. B 88, 245104 (2013). [doi/arXiv]

11. Y. Komijani, T. Choi, F. Nichele, K. Ensslin, T. Ihn, D. Reuter, A. D. Wieck, Counting statistics of hole transfer in a p-type GaAs quantum dot with dense excitation spectrum, Phys. Rev. B 88, 035417 (2013). [doi/arXiv]

10. Y. Komijani, M. Csontos, T. Ihn, K. Ensslin, Y. Meir, D. Reuter, A. D. Wieck, Origins of conductance anomalies in a p-type GaAs quantum point contact, Phys. Rev. B 87, 245406 (2013). [doi/arXiv]

9. Y. Komijani, M. Csontos, I. Shorubalko, U. Zuelicke, T. Ihn, K. Ensslin, D. Reuter, A. D. Wieck, Anisotropic Zeeman splitting in p-type GaAs quantum point contacts, Europhys. Lett. 102, 37002 (2013). [doi/arXiv]

8. F. Nichele, Y. Komijani, S. Hennel, T. Ihn, K. Ensslin, C. Gerl, W. Wegscheider, D. Reuter, A. D. Wieck, Aharonov-Bohm rings with strong spin-orbit interaction: the role of sample-specific properties, New J. of Phys. 15, 033029 (2013). [doi/arXiv]

7. Y. Komijani, M. Csontos, I. Shorubalko, T. Ihn, K. Ensslin, Y. Meir, D. Reuter, A. D. Wieck, Evidence for localization and 0.7 anomaly in hole quantum point contacts, Europhys. Lett. 91, 67010 (2010). [doi/arXiv]

6. M. Csontos, Y. Komijani, I. Shorubalko, K. Ensslin, D. Reuter, A. D. Wieck, Nanostructures in p-GaAs with improved tunability, Appl. Phys. Lett.97, 022110 (2010). [doi/arXiv]

5. A. Ebrahimi, Y. Abdi, S. Mohajerzadeh, Y. Komijani, Highly sensitive capacitive transducer based on comb-like array of branched carbon nanotubes, Proc. Eurosensors XXIII Conf. 1, 1159 (2009). [doi]

4. Y. Komijani, M. Csontos, T. Ihn, K. Ensslin, D. Reuter, A. D. Wieck, Observation of excited states in a p-type GaAs quantum dot, Europhys. Lett. 84, 57004 (2008). [doi/arXiv]

3. B. Khadem-Hosseinieh, Y. Komijani, R. Faraji-Dana, M. Shahabadi, Using photon wavefunction for the time domain analysis of electromagnetic wave scattering problems, PIER 76, 397 (2007). [doi]

2. Y. Komijani, N. Izadi, B. Khadem-Hosseinieh, S. Mohajerzadeh, Ultra-violet assisted 3D microstructures on PET, IEEE Sensors Jorunal 6, 851 (2006). [doi]

1. J. Koohsorkhi, Y. Abdi, S. Mohajerzadeh, H. Hosseinzadegan, Y. Komijani, E. Asl Soleimani, Fabrication of self-defined gated field emission devices on silicon substrates using PEVCD-grown carbon nano-tubes, Journal of Carbon 44, 2797 (2006). [doi]