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Quantized Hall Effect Circuit Technology

IP.com Disclosure Number: IPCOM000041841D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 3 page(s) / 31K

Publishing Venue

IBM

Related People

Brodsky, MH: AUTHOR

Abstract

Breaking the ring of a 2-dimensional (2-D) quantized Hall effect device electronically, by means of a control gate selectively biased to deplete the electrons in the 2-D ring, changes the source-drain current from 0 to a finite value and provides the basis for a family of circuits. Figs. 1 and 2 illustrate the quantized Hall effect device. Contact A connects the source 1. Magnetic field F is perpendicular to the plane of the paper in Fig. 1. Ammeter contact C measures the source current. Source current passes from source contact 1, through 2-D ring 2, to drain contact 3. Control gate 4 acts to provide an apparent gap E-E' in 2-D ring 2 under control of a signal at contact D; large bias gate 5 provides operating levels to create the 2-D channel of electrical carriers in Ring 2.

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Quantized Hall Effect Circuit Technology

Breaking the ring of a 2-dimensional (2-D) quantized Hall effect device electronically, by means of a control gate selectively biased to deplete the electrons in the 2-D ring, changes the source-drain current from 0 to a finite value and provides the basis for a family of circuits. Figs. 1 and 2 illustrate the quantized Hall effect device. Contact A connects the source 1. Magnetic field F is perpendicular to the plane of the paper in Fig. 1. Ammeter contact C measures the source current. Source current passes from source contact 1, through 2-D ring 2, to drain contact 3. Control gate 4 acts to provide an apparent gap E-E' in 2-D ring 2 under control of a signal at contact D; large bias gate 5 provides operating levels to create the 2-D channel of electrical carriers in Ring 2. Background Facts There exists a set of recently discovered phenomena known generically as "Quantum Hall Effects." See, e.g., the first experimental identification of the effect in K. V. Klitzing, D. Dorda, and M. Pepper, "New Method for High-Accuracy Determination of the Fine-Structure Constant Based on Quantized Hall Resistance," Physical Review Letters 45, 494-7 (1980), or a more recent report, D. C. Tsui, H. L. Stormer and A. C. Gossard, "Two- Dimensional Magnetotransport in the Extreme Quantum Limit," Physical ReviewI LettersI 48, 1559-62 (1982). The basic phenomenon is as follows: It in a Hall geometry with a component of magnetic field perpendicular to the plane of a 2-D quantum electron gas the Hall resistance, actually resistivity pxy, will exhibit plateaus with values h/ie2, where h= Planck's constant, e=charge on the electron, and i=integr. The parallel resistance pxx will exhibit deep minima where pxx exhibits plateaus. The plateaus of minima area a function of the Fermi level position with respect to the Landau levels, and they occur when the Fermi level is between Landau levels. The relative position of the Fermi level is controllable by a gate voltage to an FET structure as V. Klitzing, et al., did (see Fig. 3) or by magnetic field as Tsui, et al., did (see Fig. 4). Recently, F. Fang and P. J. Stiles, ("Quantized Magnetoresistance in Two-Dimensional Electrosystems," Physical Review Letters B27, 6487 (1983)) discovered a two-point electrical resistance consequence of the Quantum Hall Effect (see Fig. 5). In essence, their result is that in the 2-D quantum limit a two-point resistance (for any two points) measurement gives the same result as pxy = h/ie2 when the Fermi level is between Landau levels; at other positions of the Fermi level, pxy is different for different geometries. Fig. 5 illustrates the concept. Proposed Technique. To set the concept for this invention one step further, consider what happens if we could somehow steer voltages and/or currents so as to switch from a four-point to a two-point (and vice versa) measurement of resistance (o...