Fewer-junction single-electron trap with an ohmic resistor

Abstract We report on the low-temperature ( T =40– 170 mK ) operation of a single-electron trap with 4 junctions Al/AlO x /Al, equipped with a 8 μm -long Cr resistor of R∼50 kΩ ≈2h/e 2 . In accordance with the theory of dissipative environment, the rate of cotunneling in our trap was drastically suppressed, which manifested itself in considerably longer trapping times as compared to similar traps without resistor. For T⩽100 mK , the time constant of spontaneous charge state switching was as large as 10 3 –10 4 s, approaching the times reported for 7- and 9-junction traps without resistors.