Dr Soumya Sarkar

• Device materials and related physics
• Nanoelectronic, spintronic and nanophotonic device fabrication and characterization
• Atomically thin semiconductors, thin film oxides, ferroelectrics
• Sustainable AI hardware, Quantum photonic hardware

Current research projects:

Spintronic devices with ultraclean interfaces

Spintronic devices based on atomically thin materials are promising for ultra-low power and high-density non-volatile memory technology.¹ A key challenge is the fabrication of ultraclean interfaces for spin injection/detection.² Our recent experimental breakthrough (Nature Electronics, in press) in fabricating ultraclean metal contacts for graphene spin valves opens possibilities for building scalable and robust 2D spintronic devices.³ The project will investigate the growth of ferromagnetic metal films on 2D semiconductors and fundamental spin transport mechanisms across metal/2D semiconductor interfaces using advanced nano-device fabrication, spectroscopic and electrical characterisation. Our results aim to accelerate the back end of line (BEOL) integration of 2D spin-based technologies for applications such as in-memory computing to enable next-generation AI hardware.   

1. Yang, H., et al. "Two-dimensional materials prospects for non-volatile spintronic memories." Nature 606.7915 (2022): 663-673.

2. Wang, Y., Sarkar S., et al. "Critical challenges in the development of electronics based on two-dimensional transition metal dichalcogenides." Nature Electronics 7.8 (2024): 638-645.

3. Sarkar, S., et al. "Spin injection in graphene using ferromagnetic indium-cobalt van der Waals contacts." Nature Electronics (In press).

Electronic and photonic devices based on ferroelectrics

Ferroelectric materials exhibit spontaneous electrical polarisation that is programmable and non-volatile. Layered semiconducting ferroelectrics are emerging and are compatible with existing semiconductor industry processes. We have recently demonstrated memory devices such as ferroelectric field effect transistors and ferroelectric diodes based on layered ferroelectrics.^4,5 These devices operate at ultra-low power, exhibit stable data retention over multiple read-out states, and are promising for in-hardware implementation of artificial neural networks (ANN). The aim of this project is to fabricate ferroelectric diodes and investigate their electrical and optical properties to optimise the design of neuromorphic electronic and photonic devices for next generation AI hardware.

4. Sarkar, S. et al. "Multistate ferroelectric diodes with high electroresistance based on van der Waals heterostructures." Nano Letters 24.42 (2024): 13232-13237.

5. Ghani, MA., Sarkar, S., et al. "Ferroelectric field effect transistors based on two-dimensional CuInP2S6 (CIPS) and graphene heterostructures." MRS Energy & Sustainability (2024): 1-8.

Atomically thin semiconductors for quantum optical technologies 

Atomically thin semiconductors are an excellent host for ‘single atoms’ that emit ‘single photons’, a useful quantum light source. In addition, the structure of these materials allows the light they emit to be modulated and guided electrically and through integration with nanophotonic structures. In the past, my research has investigated light-matter interactions in atomically thin semiconductors⁶ and developed strategies for introducing such atomic light emitters into these materials.⁷ This project seeks to build upon these results to demonstrate light emitting devices (LEDs) that are based on atomic dopants as well as spin-LEDs capable of emitting circularly polarised light, essential for the advancement of quantum optical technologies.

6. Sarkar, S., et al. "Polaronic trions at the MoS2/SrTiO3 interface." Advanced Materials 31.41 (2019): 1903569.

7. Sarkar, S., et al. "Identifying Luminescent Boron Vacancies in h-BN Generated Using Controlled He+ Ion Irradiation." Nano Letters 24.1 (2023): 43-50.