arXiv subjects

C. -T. Liang

Publications and source records attributed to C. -T. Liang.

23 records · Page 2Linked to original sources

arXiv1998

Experimental Evidence for Coulomb Charging Effects in an Open Quantum Dot at Zero Magnetic Field

We have measured the low-temperature transport properties of an open quantum dot formed in a clean one-dimensional channel. For the first time, at zero magnetic field, continuous and periodic oscillations superimposed upon ballistic conductance steps are observed when the conductance through the dot $G$ exceeds $2e^2/h$. We ascribe the observed conductance oscillations to evidence for Coulomb charging effects in an open dot. This is supported by the evolution of the oscillating features for $G>2e^2/h$ as a function of both temperature and barrier transparency. Our results strongly suggest that at zero magnetic field, current theoretical and experimental understanding of Coulomb charging effects overlooks charging in the presence of fully transmitted 1D channels.

cond-mat.mes-hall↗

arXiv1997

Experimental studies of T--shaped quantum dot transistors: phase-coherent electron transport

We have measured the low-temperature transport properties of a T-shaped quantum dot. Replicated oscillations superimposed on one-dimensional conductance steps are observed. These structures are consistent with electron phase-coherent length resonance effects in the ballistic regime. Using a simple model, we suggest that both one-dimensional and two-dimensional electron-electron scattering gives rise to electron phase-breaking in our system.

cond-mat.mes-hall↗

arXiv1997

Experimental evidence of a metal-insulator transition in a half-filled Landau level

We have measured the low-temperature transport properties of a high-mobility front-gated GaAs/Al_{0.33}Ga_{0.67}As heterostructure. By changing the applied gate voltage, we can vary the amount of disorder within the system. At a Landau level filling factor $ν=1/2$, where the system can be described by the composite fermion picture, we observe a crossover from metallic to insulating behaviour as the disorder is increased. Experimental results and theoretical prediction are compared.

cond-mat.mes-hall↗

arXiv1997

Resonant transmission through an open quantum dot

We have measured the low-temperature transport properties of a quantum dot formed in a one-dimensional channel. In zero magnetic field this device shows quantized ballistic conductance plateaus with resonant tunneling peaks in each transition region between plateaus. Studies of this structure as a function of applied perpendicular magnetic field and source-drain bias indicate that resonant structure deriving from tightly bound states is split by Coulomb charging at zero magnetic field.

cond-mat.mes-hall↗

arXiv1996

Ballistic Composite Fermions in Semiconductor Nanostructures

We report the results of two fundamental transport measurements at a Landau level filling factor $ν$ of 1/2. The well known ballistic electron transport phenomena of quenching of the Hall effect in a mesoscopic cross-junction and negative magnetoresistance of a constriction are observed close to B~=~0 and $ν~=~ 1/2$. The experimental results demonstrate semi-classical charge transport by composite fermions, which consist of electrons bound to an even number of flux quanta.

cond-mat↗