IIT Bombay: Single Light Pulse Can Now Control Quantum States in 2D Materials

Mumbai, December 14 – Researchers at the Indian Institute of Technology (IIT) Bombay have announced a significant advancement in quantum control. They've discovered a simplified method to manipulate quantum states within ultra-thin materials using light. This breakthrough holds the potential to revolutionize computer technology, paving the way for devices that are significantly faster and more energy-efficient than current electronic systems.

The research centers on two-dimensional semiconductors, materials that are only a single atom thick – thousands of times thinner than a human hair. Within these materials, electrons can exist in two distinct quantum states, referred to as valleys and labeled K and K′. These two states are analogous to the 0 and 1 used in digital computing, and they form the foundation for the burgeoning field of valleytronics.

Previously, controlling these valley states posed a significant challenge. Existing techniques necessitated intricate laser setups involving circularly polarized light and multiple laser pulses. Even with these complex methods, control was often incomplete or difficult to accurately measure. Achieving reliable and reversible switching between the two valley states remained a major hurdle.

The IIT Bombay team's new research demonstrates that such complex setups are no longer necessary. Their study, published in the journal 'Advanced Optical Materials,' reveals that a single, linearly polarized laser pulse can effectively control and read the valley state of electrons.

The key to this new method is introducing a small, precisely controlled skew in the laser pulse's polarization, according to Prof. Gopal Dixit from IIT Bombay.