Ballistic conductance of a quantum wire at finite temperatures

The temperature-dependent ballistic conductance of a quantum wire is calcul ated without consideration of carrier scattering. The contribution to the c onductance (G) from size-quantization subbands with E-j - mu much greater t han kT is described by the Landauer-Buttiker formula G = 2e(2)/h, where e i s the elementary charge, h is Planck's constant, mu(T) is the electrochemic al potential, E-j is the j-th subband bottom, T is temperature, and k is th e Boltzmann constant. The contribution from other subbands decreases as the ir number increases, being exponentially small for higher subbands. The qua ntum staircase disappears when kT approaches the energy spacing between the size-quantization levels. Such temperature quenching of the quantum stairc ase at gate potentials corresponding to a stepwise change in the ballistic conductance is observed in studies of the quantized conductance of a silico n quantum wire. (C) 2000 MAIK "Nauka/Interperiodica".