RESONANT-TUNNELING SPECTROSCOPY OF A 2-DIMENSIONAL TEAR-SHAPED BILLIARD

We have used Hartree calculations to investigate the electrical proper ties of a sub-micron resonant tunnelling diode with an etched tear-sha ped cross-section. Non-passivated surface states are shown to produce a deep potential minimum near the centre of the tear drop. In the emit ter accumulation layer, the conduction electrons screen this potential minimum and move in an ideal hat-bottomed billiard with soft walls wh ich generate a mixed stable-chaotic classical phase space. In the quan tum well, the potential minimum is unscreened and there is a large ene rgy splitting between the ground state and first excited state. The gr ound state of the quantum well therefore provides an in-built spectros copic probe of a wide range of quantized emitter states. Our studies h ighlight the potential of tunnelling spectroscopy as an alternative to parallel transport studies of chaotic billiards which only detect sta tes near the Fermi level. (C) 1998 Elsevier Science B.V. All rights re served.