We have studied the phenomena of electronic transport in a quasi one-dimensional (1D) channel with an embedded antidot. The 1D channel is defined by either a set of split gates or ring gates, with a 100-nm-in-diameter antidot in the center. The presence of an antidot in the channel force electrons to split their paths, which then merge after the antidot. Such interference of their wave functions will change the normal transport behaviors of 1D electron gas. The two terminal magneto-conductance measurements taken at 0.3 K have shown intriguing yet different features under these two geometries. We observed inference patterns by controlling the gates separately, which can be suppressed after certain magnetic fields applied normal to the sample surface. Our devices also provide the opportunity to modulate electron modes from two paths and to study the tunable Aharonov-Bohm effect. In the current configuration we cannot detect the resonant tunneling of edge states via the embedded anitdot, which has been proposed for spin-filtering application. To further understand the physics behind the interference patterns, possibilities and limitation in device application, a refined measurement set-up at a lower temperature is needed.

We have studied the phenomena of electronic transport in a quasi one-dimensional (1D) channel with an embedded antidot. The 1D channel is defined by either a set of split gates or ring gates, with a 100-nm-in-diameter antidot in the center. The presence of an antidot in the channel force electrons to split their paths, which then merge after the antidot. Such interference of their wave functions will change the normal transport behaviors of 1D electron gas. The two terminal magneto-conductance measurements taken at 0.3 K have shown intriguing yet different features under these two geometries. We observed inference patterns by controlling the gates separately, which can be suppressed after certain magnetic fields applied normal to the sample surface. Our devices also provide the opportunity to modulate electron modes from two paths and to study the tunable Aharonov-Bohm effect. In the current configuration we cannot detect the resonant tunneling of edge states via the embedded anitdot, which has been proposed for spin-filtering application. To further understand the physics behind the interference patterns, possibilities and limitation in device application, a refined measurement set-up at a lower temperature is needed.

[1] D. F. Holcomb, “Quantum electrical transport in smaple of limited dimensions,” Am. J. Physics, vol. 67, p. 278, 1999.
[2] C. W. J. Beenakker and H. van Houten, “Quantum transport in semiconductor nanostructures,” Solid State Physics, vol. 44, pp. 1–288, 1991.
[3] B. J. van Wees, H. van Houten, C. W. J. Beenakker, J. G.
Williamson, L. P. Kouwenhoven, D. van der Marel, and C. T.
Foxon, “Quantized conductance of point contacts in a two dimensional electron gas,” Phys. Rev. Lett., vol. 60, pp. 848–850, Feb 1988.
[4] P. F. Bagwell, “Evanescent modes and scattering in quasi-one dimensional wires,” Phys. Rev. B, vol. 41, pp. 10354–10371, May 1990.
[5] J. H. Bardarson, I. Magnusdottir, G. Gudmundsdottir, C.-S. Tang, A. Manolescu, and V. Gudmundsson, “Coherent electronic transport in a multimode quantum channel with gaussiantype scatterers,” Phys. Rev. B, vol. 70, no. 24, p. 245308, 2004.
[6] A. S. Sachrajda, Y. Feng, R. P. Taylor, G. Kirczenow, L. Henning, J. Wang, P. Zawadzki, and P. T. Coleridge, “Magnetoconductance of a nanoscale antidot,” Phys. Rev. B, vol. 50, pp. 10856–10863, October 1994.
[7] K. v. Klitzing, G. Dorda, and M. Pepper, “New method for high accuracy determination of the fine-structure constant based on quantized hall resistance,” Phys. Rev. Lett., vol. 45, pp. 494–497, Aug 1980.
[8] D. C. Tsui, H. L. Stormer, and A. C. Gossard, “Two dimensional magnetotransport in the extreme quantum limit,”
Phys. Rev. Lett., vol. 48, pp. 1559–1562, May 1982.
[9] S. M. Reimann and M. Manninen, “Electronic structure of quantum dots,” Rev. Mod. Phys., vol. 74, pp. 1283–1342, Nov 2002.
[10] J. Faist, P. Gu´eret, and H. Rothuizen, “Possible observation of impurity effects on conductance quantization,” Phys. Rev. B, vol. 42, pp. 3217–3219, Aug 1990.
[11] V. Gudmundsson, C.-S. Tang, and A. Manolescu, “Bound state with negative binding energy induced by coherent transport in a two-dimensional quantum wire,” Phys. Rev. B, vol. 72, no. 15, p. 153306, 2005.
[12] J. K. Jain and S. A. Kivelson, “Quantum hall effect in quasi one dimensional systems: Resistance fluctuations and breakdown,”Phys. Rev. Lett., vol. 60, pp. 1542–1545, Apr 1988.
[13] V. J. Goldman and B. Su, “Resonant Tunneling in the Quantum Hall Regime: Measurement of Fractional Charge,” Science,vol. 267, no. 5200, pp. 1010–1012, 1995.
[14] I. V. Zozoulenko and M. Evaldsson, “Quantum antidot as a controllable spin injector and spin filter,” Applied Physics Letters, vol. 85, no. 15, pp. 3136–3138, 2004.
[15] R. P. Taylor, J. A. Adams, M. Davies, P. A. Marshall, and R. Barber, “Fabrication of nanostructures with multilevel architecture,” Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, vol. 11, no. 3, pp. 628–633, 1993.
[16] S. Datta, Electronic Transport in Mesoscopic Systems. Cambridge University Press, 1995.
[17] J. H. Davies, The Physics of Low-dimensional Semiconductors : An Introduction. The Press Syndicate of the University of Cambridge, 1998.
[18] F. F. Fang and P. J. Stiles, “Quantized magnetoresistance in two-dimensional electron systems,” Phys. Rev. B, vol. 27, pp. 6487–6488, May 1983.