aagnik.com

Nick (Aagnik) Pant

Univ. of Texas at Austin (Postdoc) ← Univ. of Michigan (Ph.D.) ← McGill Univ. (B.Eng.)

Hello! My research uncovers how how microscopic electronic and atomic interactions give rise to macroscopic material and device behaviour. This allows allows us to tackle critical societal challenges relating to energy efficiency and security. I use high-performance computing and artificial intelligence to model materials from electrons to atoms to devices. This first-principles approach does not just describe but predicts the physical mechanisms that cause energy loss in complex material systems that support classical and quantum photonic systems, the clean energy, and emerging AI hardware.

I have a track record in tackling fundamental engineering challenges through collaborations with experimentalists and industry partners, such as Lumileds, one of industry's most significant and pioneering LED manufacturers. To learn more, read this invited feature article I wrote for Compound Semiconductor.

I am a recipient of the NSERC Postgraduate Scholarship and the MICDE Graduate Fellowship.

Recent Publications

Uncovering energy-loss mechanisms in deep-ultraviolet LEDs

We have developed a theoretical framework to compute non-radiative recombination rates in quantum wells that are used in actual LEDs. This is contrast to previous methods that could only model bulk materials. Our findings uncover the essential role of Auger-Meitner recombination in limiting the efficiency of UV LEDs, essential for manufacturing and healthcare applications. (Appl. Phys. Lett. 125, 021109 (2024))

Challenging the conventional view on what makes LEDs efficient

By developing a theoretical framework to assess the impact of disorder on optoelectronic materials, I have challenged a long-standing hypothesis that carrier localization is responsible for the highly efficient nature of nitride LEDs. The takeaway is simple: designs that minimize the defect density acheive high efficiency. (Phys. Rev. Applied 20, 064049 (2023))

The many-body origin of the power-dependent hue shift of nitride LEDs

Using multi-scale modelling, I identified the detrimental role of degenerate carrier densities in causing the notorious hue-shift problem of nitride LEDs, where a green LED undesirably becomes blue with increasing current. I also showed that quantitative agreement with experiments requires considering many-body effects that are ignored by most commercial solvers. (AIP Advances 12, 125020 (2022))

Computational discovery of layered extreme power semiconductors

Using state-of-the-art density-functional theory and many-body perturbation theory, I have predicted that atomically thin superlattices of AlN and GaN are the most promising technologically viable semiconductors for power devices, based on the modified Balifa figure of merit, because of their ultra-wide band gaps and high electron mobility. Such superlattices can be grown with MBE or MOVPE. (Appl. Phys. Lett. 121, 032105 (2022))

Updates

Check out my recent feature in the Compound Semiconductor magazine, where I discuss my perspective on LED modeling, quantum machine learning, and where the field should go next.
I presented two talks at the 2024 International Workshop on Nitride Semiconductors in Hawaii. I presented one work on theoretically characterizing energy loss mechanisms in UV LEDs and another talk critically reevaluating the hypothesis on whether alloy fluctuations really localize holes in InGaN LEDs.
I delivered a talk at the MRS Spring meeting (EL04) on fresh findings on Auger-Meitner recombination in AlGaN UV LEDs, which was recognized with the Best Oral Presentation award. Thank you to the organizers, Dr. Bob Kaplar (Sandia National Labs) and Prof. Sriram Krishnamoorthy (UCSB), for nominating me for this award.
I had a great time delivering an invited talk at Photonics West on the simulation of LED materials. Thank you to the organizers, including Prof. Bernd Witzigmann (Friederich-Alexander-Universitaet), for the invitation!
Thank you to Prof. Jim Speck and Prof. Claude Weisbuch (UCSB) for inviting me to present at a workshop on Disorder in Semiconductor Physics at UCSB, alongside pioneers in semiconductors and condensed-matter physics.
I presented a talk at the 2022 International Workshop on Nitride Semiconductors in Berlin, challenging the notion that carrier localization gives rise to defect tolerance in InGaN LEDs. I also presented a poster on my recent work modelling the optical spectra of LEDs.
Check out our invited review article on characterizing and predicting ultra-wide-band-gap semiconductors (J. Mat. Res. 36, 4616 (2021)).

Recent Collaborators

Industry

Lumileds (Rob Armitage, Director)

Experimentalists

Feezell group at the University of New Mexico
Rajan group at the Ohio State University

Theorists

Van de Walle group at the University of California, Santa Barbara
Louie group at the University of California, Berkeley
Li group at the University of Southern California

A little more about me

I was born in Kathmandu, Nepal and I immigrated to North America when I was ten years old (I grew up mostly in Canada, and have lived in nine different cities across the world). I strongly believe in the importance of including a wide range of viewpoints from individuals with different experiences and perspectives in academia. In terms of hobbies, I enjoy cycling, hiking, and travelling the world, and I am a big fan of languages and linguistics. In addition to English, I speak Nepali, and a little bit of Hindi and French. My favourite movie is Timecrimes, an independent and underrated Spanish movie that is hilarious and bound to give you some great laughs.

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