Ashish did his PhD from TIFR, Mumbai in the Department of Condensed Matter Physics and Materials Science in 2014. He was a CNRS postdoctoral researcher in National High Magnetic Field Laboratory (LNCMI-CNRS), Grenoble, France for a year (2014-15). He won the prestigious A. v. Humboldt grant for a postdoc in the University of Muenster, Germany (2015-17). Thereafter, he won the highly competitive German Research Foundation (DFG) grant and stayed as a junior group leader in the University of Muenster until August 2021. He joined IISER Pune as an Assistant Professor in September 2021.
Experimental condensed matter physics, magnetooptics, 2D materials (semiconductors and magnets)
The research interests of Dr. Ashish Arora and his team involve experimental investigatations of low-dimensional semiconductors, magnetic materials, and their nanostructures. Such materials are central to modern electronic and computational technologies.
The team investigates very interesting physics of multiparticle species in these materials on the quantum scales, such as Coulomb-bound excitons and trions. They use polarized light as the probe, and apply electric and magnetic fields in their experiments. Their highly sensitive state-of-the-art (magneto-)optical spectroscopy techniques enable them to detect really weak signatures in the optical spectra. For a non-expert perspective of their work, Dr. Arora points us to this interview.
Since 2010, direct band gap 2D semiconductors e.g. MoS2, WSe2, etc. have been discovered which are just one layer thick (100,000 times thinner than a human hair). They are efficient emitters of light and naturally find applications in making ultrathin electronics and light emitting devices for the future. Furthermore, the physics is extremely rich. For one, there are strongly-bound many-body species such as excitons and trions. Earlier, if one had to study this physics, for instance in quantum wells made of GaAs, one could only do this at low temperatures. However, now it is possible to do this at elevated temperatures. Secondly, all the optical action takes place at the corners of their hexagonal Brillouin zone. There are neighboring K+/- valleys which can be manipulated using circularly polarized light. This finds profound applications in the future generation of devices based on manipulating the valley degrees of freedom and in quantum computation.
Dr. Ashish Arora has a strong interest in public outreach. For instance, check 'India's Science Theatre' on YouTube and Facebook.
Arora, A. (2021). Magneto-optics of layered two-dimensional semiconductors and heterostructures: Progress and prospects, J. Appl. Phys. 129 (12): 120902 [Invited Perspective]
Arora, A. et al. (2020). Dark trions govern the temperature-dependent optical absorption and emission of doped atomically thin semiconductors, Physical Review B 101 (24): 241413
Arora, A. et al. (2019). Excited-state trions in monolayer WS2, Phys. Rev. Lett., 123: 167401
Arora, A. et al. (2019). Zeeman spectroscopy of excitons and hybridization of electronic states in few-layer WSe2, MoSe2 and MoTe2, 2D Materials, 6: 015010
Arora, A. et al. (2017). Interlayer excitons in a bulk van der Waals semiconductor, Nat. Commun. 8: 639
Arora, A. et al. (2017). Highly anisotropic in-plane excitons in atomically thin and bulk-like 1T'-ReSe2, Nano Lett. 17: 3202
Schmidt R.,* Arora, A.* et al. (2016). Magnetic-field-induced rotation of polarized light emission from monolayer WS2, Phys. Rev. Lett. 117: 077402 [*equal contribution]
Arora, A. et al. (2016). Valley Zeeman splitting and valley polarization of neutral and charged excitons in monolayer MoTe2 at high magnetic fields, Nano Lett. 16: 3624
Koperski, M., Nogajewski, K., Arora, A. et al. (2015) Single photon emitters in exfoliated WSe2 structures. Nat. Nanotechnol. 10: 503