arXiv subjects

P. Sandström

Publications and source records attributed to P. Sandström.

5 recordsLinked to original sources

arXiv1997

Nonlinear conductance of nanowires - A signature of Luttinger liquid effects?

We analyze recent measurements of the room temperature current-voltage characteristics of gold nanowires, whose zero current conductance is quantized in units of $2e^2/h$. A faster than linear increase of current with voltage was observed at low voltages beginning from $V_c=0.1$V. We analyze the nonlinear behavior in terms of a dynamic Coulomb blockade of conducting modes and show that it may be explained as a Luttinger-liquid effect.

cond-mat↗

arXiv1997

Resonant Tunneling and Persistent Current of a Non-interacting and Weakly Interacting One-dimensional Electron Gas

The persistent current for a one-dimensional ring with two tunnel barriers is considered in the limit of weakly interacting electrons. In addition to a small off-resonance current, there are two kinds of resonant behavior; (i) a current independent of the barrier transparency (true resonance) and (ii) a current analogous to the one for a ring with only a single barrier (``semi''-resonance). For a given barrier transparency one or the other type of resonant behavior is realized depending on a geometric factor (ratio of interbarrier distance to ring circumference) and on the strength of the electron-electron interaction. It is shown that a repulsive interaction favours the``semi''-resonance behavior. For a small barrier transparency the ``semi''-resonance peaks are easily washed out by temperature whereas the true resonance peaks survive.

cond-mat.mes-hall↗

arXiv1996

Persistent current in a one-dimensional ring of fractionally charged "exclusons''

The Aharonov-Bohm effect in a one-dimensional (1D) ring containing a gas of fractionally charged excitations is considered. It is shown that the low temperature behavior of the system is identical to that of free electrons with (integer) charge $e$. This is a direct consequence of the fact that the total charge in the ring is quantized in units of the electron charge. Anomalous oscillations of the persistent current amplitude with temperature are predicted to occur as a direct manifistation of the fractional nature of the quasiparticle charge. A 1D conducting ring with gate induced periodical potential is discussed as a possible set-up for an experimental observation of the predicted phenomenon.

cond-mat↗

arXiv1995

Coulomb Blockade-Effects on Quantization of Charge and Persistent Current in a Luttinger-Liquid Ring

We show that in a ring-shaped Luttinger Liquid (LL) in contact with an electron reservoir --- the chemical potential in the ring being controlled by a gate voltage $V_g$ --- both the average ring charge and the persistent current in the ring are step-like functions of $V_g$ at low temperatures. The step positions are determined by the LL parameter $α=v_F/s$, which therefore can be directly measured. We study electrons both with and without spin, taking into account long-range interactions in the ring.

cond-mat↗

arXiv1994

Influence of Long-Range Coulomb Forces and Dissipation on the Persistent Current of a Wigner Crystal-Ring

The influence of long-range Coulomb forces on the persistent current of a pinned Wigner crystal-ring is considered. A simple method is proposed for how to take into account Coulomb effects for the macroscopic quantum tunneling of the Wigner crystal. It is shown that unscreened Coulomb interactions increase the stiffness of the Wigner lattice. This leads to additional suppression of the amplitude of Aharonov-Bohm oscillations, but makes the predicted anomalous temperature dependence of the persistent current more pronounced. The impact of dissipation on the persistent current of a Wigner crystal-ring is also studied.

cond-mat↗