Ultrafast Terahertz Spintronics Group
(UTSG)

We are a group of theoretical condensed matter physicists focusing on ultrafast manipulation of magnetic spins. While the industrial economy of the 20th-century was led by oil, the digital economy of the 21st-century will be dominated by data. To this end, the data is the new oil, the vital fuel of our economy. Every day a huge amount of data are being created and stored by us in the form of social media (Facebook, WhatsApp, Twitter, etc.), e-commerce (Amazon, Flipkart, etc.), and many more. It is not only the common people but also the companies that focus on the digital economy in terms of consumers buying products. Such an amount of big data creates the datasphere that is increasing exponentially every year. It is estimated that the amount of digital data will be about 175 ZB (Zeta Byte) by the end of the year 2025. The ever-increasing amount of big data requires novel energy-efficient technological storage solutions. To this end, magnetic data storage devices have always been the cheapest way. The current magnetic data storage devices use a magnetic disk of ferromagnets, manipulated by an external electrical signal. However, such ferromagnetic storage is limited by the speed of nanoseconds.   

At Ultrafast Terahertz Spintronics Group (UTSG), we focus on technological data storage solutions in an energy-efficient way at sub-picosecond timescales. A pioneering experiment of ultrafast demagnetization paved the way for such technological solutions in 1996. We theoretically investigate ultrafast magnetic manipulation and switching in several classes of magnets including the non-collinear spin structures. We mainly use analytical and computational techniques to engineer spin manipulation and switching. We are in close collaboration with national and international experimental groups.                

Recent News

• Our recent work on experimental observation of relativistic field-derivative torque has been accepted in Advanced Functional Materials (2025)! 

• Subhadip has published his first work in Phys. Rev. B (2024). Congratulations Subhadip!

• Pratyay and Somasree has published their first work in Phys. Rev. Mater. (2024). Congratulations Pratyay and Somasree!

• Mr. Subhadip Santra joined the group as a PhD Research Scholar. Welcome Subhadip!

• Ritwik was awarded PECFAR 2024 scientific exchange award by Indo German Science and Technology Centre (IGSTC).

• Our recent work Spin inertia and auto-oscillations in ferromagnets has been accepted for publication in Phys. Rev. Lett (2024) Editor's Suggestion!

• Our recent work Magnetization precession after non-collinear dual optical excitation has been selected as Editor's Pick (2024).

• Mr. Pratyay Mukherjee joined the group as a PhD Research Scholar. Welcome Pratyay!

• Ritwik has been awarded with Start-Up Research Grant (SRG) from SERB-DST (2023)!

• Mr. Subhadip Ghosh joined the group as a PhD Research Scholar. Welcome Subhadip!

• Our recent work on "inertial spin wave in ferromagnets and antiferromagnets" has been published in Phys. Rev. B (2022) 

• Mr. Prasad Dhali (BS-MS student at IISER Tirupati) joined as a summer internship trainee

• Our recent work on "Spin pumping at terahertz nutation resonances" has been published in Phys. Rev. B (2021)

• Our recent work on "Influence of intersublattice coupling on the terahertz nutation spin dynamics in antiferromagnets" has been accepted in Phys. Rev. B (2021)

• Our recent work on "Terahertz spin dynamics driven by an optical spin-orbit torque" has been published in Physical Review Research (2021)

• Our recent work on "Theory of magnetic inertial dynamics in two-sublattice ferromagnets" has been published in J. Phys.: Condens. Matter. (2021)

• Our recent work on "Nutation in antiferromagnetic resonance" has been published in Phys. Rev. B (2021)

• Ritwik Mondal was awarded VR International postdoc research grant 2020 from Swedish Research Council, Sweden.  

• Ritwik Mondal is a recipient of Zukunftskolleg mentorship program 2019 from Deutsche Forschungsgemeinschaft (DFG) at Universität Konstanz, Germany. 

• Ritwik Mondal was awarded Humboldt Research Fellowship for Postdoctoral Researchers (2019 - 2020) from  Alexander von Humboldt Stiftung, Germany 

• Our recent publication in Phys. Rev. B 96, 024425 (2017) has been selected as Editor's Suggestion

• Our publication in J. Phys.: Condens. Matter 28, 194002 (2017) has been featured as JPhys+ News and Views: Can Relativity Explain Coherent Ultrafast Magnetism?

• Our article Phys. Rev. B 92, 100402(R) (2015) has been appeared in the news by Phys.org: Physicists Trace Origin of Electromagnetic Interaction to Dirac Equation and selected as Editor's Suggestion