From the lab bench

S. Mathimalar and Satyaki Sasmal (from Karthik V. Raman’s lab) give us a brief preview of their work on a three dimensional topological insulator. The characteristics exhibited by this class of materials hold potential for application in quantum information processing.

Karthik V. Raman’s lab

1. What was the motivation behind probing a 3D topological insulator?

Topological materials are currently an exciting field of research in condensed matter physics, both in theory as well as in experiments. In this project, we were working on a 3D-topological insulator, which is an insulator in bulk while conducting on the surface. We had proximitised this 3D-TI with a ferromagnetic thin film on the top surface. We can play with the conducting electrons on a surface state by a ferromagnetic layer and a gate voltage.  If one wants to put it in a simple way, we select an interesting part (surface electrons) of the electron pool in the sample and tune it according to our interest and requirement. The property these materials have potential applications in low-power consumption electronic devices, quantum information processing, and numerous other applications. This intrigued us to investigate the material further.

2. What were the challenges that you faced during the course of characterising this material?

Experimental physics is more of keeping the artist alive in you with the science in mind. Every part of the experiment from making the correct sample to characterising and bringing out the expected physics needs patience and perseverance. One develops this habit along with the research. Apart from the understanding of the physics in this project, growing thin film samples in an extreme vacuum (10-10 mbar, much lower than atmospheric pressure) and measuring at low temperature (2K, close to absolute zero) adds to the complexity.

3. How would you describe your experience of working on this project?

The lab was developing along with the project, it is good for the initial student/postdoc to get the experience of building a lab along with the physics hunt. Now, we have a wonderful lab to grow and characterize the materials. Being the first authors, we would like to thank all our collaborators, who made this project successful. In particular, Karthik, who believed in us for this project.

The publication is available here.