An in situ tunable radio-frequency quantum point contact
نویسندگان
چکیده
منابع مشابه
A circuit analysis of an in situ tunable radio-frequency quantum point contact.
A detailed analysis of the tunability of a radio-frequency quantum point contact setup using a C - LCR circuit is presented. We calculate how the series capacitance influences resonance frequency and charge-detector resistance for which matching is achieved as well as the voltage and power delivered to the load. Furthermore, we compute the noise contributions in the system and compare our findi...
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We present a current and charge conserving theory for the low frequency admittance of a quantum point contact. We derive expressions for the electrochemical capacitance and the displacement current. The latter is determined by the emittance which equals the ca-pacitance only in the limit of vanishing transmission. With the opening of channels the capacitance and the emittance decrease in a step...
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We introduce quantum point contact microscopy (QPCM) as a novel method for surface characterization, where the conductance through a quantum point contact formed by a metal atom between the tip of a scanning tunneling microscope and the surface is mapped across the surface. Application of QPCM to copper and gold (111) shows reproducibly atomic resolution, on gold (111) the alternating atomic st...
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A design approach for a tunable active filter of constant bandwidth and center-frequency gain is described. The approach is based on a feedback configuration with a complex pole pair in the forward transfer function, and a complex zero pair in the feedback transfer function. Center frequency tuning is achieved with the variation of only one element, a potentiomenter, which controls the feedback...
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We report on direct measurements of the electronic shot noise of a quantum point contact at frequencies nu in the range 4-8 GHz. The very small energy scale used ensures energy independent transmissions of the few transmitted electronic modes and their accurate knowledge. Both the thermal energy and the quantum point contact drain-source voltage V_{ds} are comparable to the photon energy hnu le...
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ژورنال
عنوان ژورنال: Applied Physics Letters
سال: 2010
ISSN: 0003-6951,1077-3118
DOI: 10.1063/1.3517483