Optical control of TMDCs valley pseudospin qubits

Quantum dots or single electron transistors, allow for individual control of single charge or spin. In addition, some semiconductor monolayers possess a sizeable direct bandgap of ≈1.5–2 eV in the optical range allowing electrostatic confinement and optical manipulation of carriers. Therefore, we try to adopt the method of this theoretical paper, and see if we can control single qubit or couple 2 qubits optically.

Linked project

This project is conducted by the same people as 👉 Control over the atomic spins within certain molecules by NMR technique

Group members

• XU ZIZHOU
  • Matric Number: A0229645W
  • Email: zizhou_xu@u.nus.edu
• CHU WENHAO

Q & A

What are K & K' points?

K & K' points

• K-points are sampling points of Brillouin zone in reciprocal lattice

Choose monolayer TMDCs materials or 2D heterostructure?

• There are four main carrier properties that optimal Opto-valleytronics should possess.
  1. long carrier lifetime
  2. long valley lifetime
  3. high valley polarization
  4. long valley coherence time
• By adopting 2D heterostructure TMDCs materials, we can create these conditions for building promising quantum platform. (eg. Due to the type II band alignment and weak hybridization of van der Waals heterostructure, the electron–hole layer separation, the electron–hole exchange interaction is greatly reduced, resulting in a long cryogenic lifetime (ns to $\mu$s)and valley lifetime (~ 10 ns) of the interlayer exciton.)

References

Spin-valley qubit in nanostructures of monolayer semiconductors: Optical control and hyperfine interaction[1]
Opto-valleytronics in the 2D van der Waals heterostructure[2]