QUANTUM OSCILLATIONS IN SURFACE-TIP TRANSFER OF ADATOMS ON AFM STM WITH A DISSIPATIVE ENVIRONMENT/

The influence of a dissipative environment on quantum coherence in sur face-tip adatom transfer in AFM/STM is studied within an adiabatic app roach. taking into account the slow motion of the tip with respect to an adsorption site. It is shown that coherent tunneling is the dominan t mechanism of adatom transfer at temperatures below 10 K for insulato rs and semiconductors, and below 0.1 K for metals. The negative influe nce of electron and phonon polaron effects, which manifests itself in the destruction of coherence, may be noticeably compensated by potenti al fluctuations due to atom vibrations. As a result, the renormalized coherent tunneling amplitude may be even greater than the ground energ y level splitting in the absence of a dissipative environment. Prospec tive pratical applications of the quantum coherence in adatom transfer are discussed. (C) 1997 Elsevier Science B.V.