Ballistic conductance of a quantum wire at finite temperatures

The temperature-dependent ballistic conductance of a quantum wire is calculated without consideration of carrier scattering. The contribution to the conductance (G) from size - quantization subbands with E_j - μ ≫ kT is described by the Landauer - Büttiker formula G = 2e²/h, where e is the elementary charge, h is Planck's constant, μ(T) is the electrochemical potential, E_j is the j-th subband bottom, T is temperature, and k is the Boltzmann constant. The contribution from other subbands decreases as their number increases, being exponentially small for higher subbands. The quantum staircase disappears when kT approaches the energy spacing between the size - quantization levels. Such temperature quenching of the quantum staircase at gate potentials corresponding to a stepwise change in the ballistic conductance is observed in studies of the quantized conductance of a silicon quantum wire.