ELECTRON AND THERMAL TRANSPORT IN INAS SINGLE-CRYSTAL FREESTANDING WIRES

We report electron and thermal transport in InAs nanostructure free-st anding wires fabricated by electron beam lithography and wet-chemical etching on an InAs/AlGaSb heterostructure grown by molecular beam epit axy. Conductance measurements of InAs free-standing wires with the thi ckness of 150-550 angstrom and a few thousand angstroms wide were cond ucted by non-dissipative AC measurement over the temperature range bet ween 4.2 and 40 K. The dependence of resistance on heating current rev ealed that the Wiedemann-Franz law holds when the power dissipation is below almost-equal-to 3 nJ. Above the critical power dissipation, the I-V characteristics show deviation from the simulation curve which ta kes into account the electric contribution, the phonon drag thermopowe r, the diffusive thermopower, the electron-phonon generation term, bla ckbody radiation, and thermal diffusion from the surface to the helium atmosphere of the cryostat. The experimental results suggest some oth er heat conduction mechanism which does not contribute to the electric conduction.