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M Núñez-Regueiro

Publications and source records attributed to M Núñez-Regueiro.

6 recordsLinked to original sources
PubMed2006

Tomonaga-Luttinger liquid and Coulomb blockade in multiwall carbon nanotubes under pressure.

We report that the conductance of macroscopic multiwall nanotube (MWNT) bundles under pressure shows power laws in temperature and voltage, as corresponding to a network of bulk-bulk connected Tomonaga-Luttinger liquids (LLs). Contrary to individual MWNTs, where the observed power laws are attributed to Coulomb blockade, the measured ratio for the end and bulk obtained exponents, approximately 2.4, can be accounted for only by LL theory. At temperatures characteristic of interband separation, it increases due to thermal population of the conducting sheets unoccupied bands.

Journal Article↗
PubMed2005

Pressure control of conducting channels in single-wall carbon nanotube networks.

We measure electrical transport on networks of single-wall nanotube ropes as a function of temperature T, voltage V, and pressure up to 22 GPa. We observe Luttinger liquid (LL) behavior, a conductance proportional to T(alpha), and a dynamic conductance proportional to V(alpha). With pressure, conductance increases while alpha decreases, enabling us to test the theoretical prediction for LL behavior on the alpha dependence of the T and V independent coefficient of the tunneling conductance, and to obtain the high frequency cutoff of LL modes. The possible transition to a Fermi liquid at alpha-->0 is unattainable, as nanotubes collapse to an insulating state at high pressures.

Journal Article↗
PubMed2001

Pressure dependence of the superconducting transition temperature of magnesium diboride.

We studied the pressure and temperature dependence of the electrical resistivity of the superconducting compound magnesium diboride (MgB(2)). The superconducting transition temperature decreases monotonically with pressure, being parabolic or linear, depending on samples. The rate of decrease under pressure is higher than in conventional superconductors. We discuss our results in terms of the semimetallic character of the electronic band structure of MgB(2).

Journal Article↗