Valleytronics

Valleytronics is a portmanteau combining the terms valley and electronics. The term refers to the technology of control over the valley degree of freedom (a local maximum/minimum on the valence/conduction band) of certain semiconductors that present multiple valleys inside the first Brillouin zone—known as multivalley semiconductors.[1][2] The term was coined in analogy to the blooming field of spintronics. While in spintronics the internal degree of freedom of spin is harnessed to store, manipulate and read out bits of information, the proposal for valleytronics is to perform similar tasks using the multiple extrema of the band structure, so that the information of 0s and 1s would be stored as different discrete values of the crystal momentum.

The term is often used as an umbrella term to other forms of quantum manipulation of valleys in semiconductors, including quantum computation with valley-based qubits,[3][4][5][6] valley blockade and other forms of quantum electronics. First experimental evidence of valley blockade predicted in Ref. [7] (which completes the set of Coulomb charge blockade and Pauli spin blockade) has been observed in a single atom doped silicon transistor.[8] Several theoretical proposals and experiments were performed in a variety of systems, such as graphene,[9] some Transition metal dichalcogenide monolayers,[10] diamond,[11] Bismuth,[12] Silicon,[4][13][14] Carbon nanotubes,[6] Aluminium arsenide[15] and silicene.[16]

References

  1. ↑ "Condensed-matter physics: Polarized light boosts valleytronics". Kamran Behnia, Nature Nanotechnology 7, 488–489 (2012).
  2. ↑ "Valleytronics: Electrons dance in diamond". Christoph E. Nebel. Nature Materials 12, 690–691 (2013). doi:10.1038/nmat3724
  3. ↑ Gunawan, O.; Habib, B.; De Poortere, E. P.; Shayegan, M. (2006-10-30). "Quantized conductance in an AlAs two-dimensional electron system quantum point contact". Physical Review B 74 (15): 155436. doi:10.1103/PhysRevB.74.155436.
  4. 1 2 "Valley-Based Noise-Resistant Quantum Computation Using Si Quantum Dots". Dimitrie Culcer, A. L. Saraiva, Belita Koiller, Xuedong Hu, and S. Das Sarma. Phys. Rev. Lett. 108, 126804 (2012).
  5. ↑ "Universal quantum computing with spin and valley states". Niklas Rohling and Guido Burkard. New J. Phys. 14, 083008(2012).
  6. 1 2 "A valley–spin qubit in a carbon nanotube". E. A. Laird, F. Pei & L. P. Kouwenhoven. Nature Nanotechnology 8, 565–568 (2013).
  7. ↑ Prati E (2011). "Valley blockade quantum switching in Silicon nanostructures". J Nanosc Nanotech 11 (10): 8522–8526. doi:10.1166/jnn.2011.4957.
  8. ↑ Crippa A; et al. (2015). "Valley blockade and multielectron spin-valley Kondo effect in silicon". Physical Review B 92: 035424. doi:10.1103/PhysRevB.92.035424.
  9. ↑ "Valley filter and valley valve in graphene". A. Rycerz, J. Tworzydło and C. W. J. Beenakker. Nature Physics 3, 172 - 175 (2007).
  10. ↑ "Valley polarization in MoS2 monolayers by optical pumping". Hualing Zeng, Junfeng Dai, Wang Yao, Di Xiao and Xiaodong Cui. Nature Nanotechnology 7, 490–493 (2012).
  11. ↑ "Generation, transport and detection of valley-polarized electrons in diamond". Jan Isberg, Markus Gabrysch, Johan Hammersberg, Saman Majdi, Kiran Kumar Kovi and Daniel J. Twitchen. Nature Materials 12, 760–764 (2013). doi:10.1038/nmat3694
  12. ↑ "Field-induced polarization of Dirac valleys in bismuth". Zengwei Zhu, Aurélie Collaudin, Benoît Fauqué, Woun Kang and Kamran Behnia. Nature Physics 8, 89-94 (2011).
  13. ↑ "Valley polarization in Si(100) at zero magnetic field". K. Takashina, Y. Ono, A. Fujiwara, Y. Takahashi and Y. Hirayama. Physical Review Letters 96,236801 (2006).
  14. ↑ "Spin-valley lifetimes in a silicon quantum dot with tunable valley splitting". C.H. Yang, A. Rossi, R. Ruskov, N.S. Lai, F.A. Mohiyaddin, S. Lee, C. Tahan, G. Klimeck, A. Morello and A.S. Dzurak. Nature Communications 4, 2069 (2013).
  15. ↑ "AlAs two-dimensional electrons in an antidot lattice: Electron pinball with elliptical Fermi contours". O. Gunawan, E. P. De Poortere, and M. Shayegan. Phys. Rev. B 75, 081304(R)(2007).
  16. ↑ "Spin valleytronics in silicene: Quantum spin Hall–quantum anomalous Hall insulators and single-valley semimetals". Motohiko Ezawa, Phys. Rev. B 87, 155415 (2013)

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