Fewer-junction single-electron trap with an ohmic resistor

We report on the low-temperature (T = 40-170 mK) operation of a single-elec tron trap with 4 junctions Al/AlOx/Al, equipped with a 8 mu m-long Cr resis tor of R similar to 50 k Omega approximate to 2h/e(2). In accordance with t he theory of dissipative environment, the rate of cotunneling in our trap w as drastically suppressed, which manifested itself in considerably longer t rapping times as compared to similar traps without resistor. For T less tha n or equal to 100 mK, the time constant of spontaneous charge state switchi ng was as large as 10(3)-10(4) s, approaching the times reported for 7- and 9-junction traps without resistors. (C) 2000 Elsevier Science B.V. All rig hts reserved.