Condensed Matter

2005 Submissions

[2] viXra:2005.0197 [pdf] submitted on 2020-05-19 19:11:26

Electric-Field Induced Strange Metal States and Possible High-Temperature Superconductivity in Hydrogenated Graphitic Fibers

Authors: Nadina Gheorghiu, Charles R. Ebbing, Timothy J. Haugan
Comments: 10 Pages.

In this work, we have studied the effects from increasing the strength of the applied electric field on the charge transport of hydrogenated graphitic fibers. Resistivity measurements were carried out for direct currents in the nA - mA range and for temperatures from 1.9 K to 300 K. The high-temperature non-ohmic voltage-current dependence is well described by the nonlinear random resistor network model applied to systems that are disordered at all scales. The temperature-dependent resistivity shows linear, step-like transitions from insulating to metallic states as well as plateau features. As more current is being sourced, the fiber becomes more conductive and thus the current density goes up. The most interesting features is observed in high electric fields. As the fiber is cooled, the resistivity first decreases linearly with the temperature and then enters a plateau region at a temperature T ~ 260 − 280 K that is field-independent. These observations on a system made out of carbon, hydrogen, nitrogen, and oxygen atoms suggest possible electric-field induced superconductivity with a high critical temperature that was predicted from studying the role of chirality on the origin of life.
Category: Condensed Matter

[1] viXra:2005.0103 [pdf] submitted on 2020-05-08 18:39:20

Superconductivity in Hydrogenated Graphites

Authors: Nadina Gheorghiu, Charles R. Ebbing, Timothy J. Haugan
Comments: 16 Pages.

We report transport and magnetization measurements on graphites that have been hydrogenated by intercalation with an alkane (octane). The temperature-dependent electrical resistivity shows anomalies manifested as reentrant insulator-metal transitions. Below T ∼ 50 K, the magnetoresistance data shows both antiferromagnetic (AFM) and ferromagnetic (FM) behavior as the magnetic field is decrease or increased, respectively. The system is possibly an unconventional magnetic superconductor. The irreversibility observed in the field-cooled vs. the zero-field cooled data for a sufficiently high magnetic field suggests that the system might enter a superconducting state below Tc ∼ 50 K. Energy gap data is obtained from nonlocal electric differential conductance measurements. An excitonic mechanism is likely driving the system to the superconducting state below the same T ∼ 50 K, where the gap is divergent. We find that the hydrogenated carbon fiber is a multiple gap system with critical temperatures estimates above room temperature. The temperature dependence of the superconducting gap follows the flat-band energy relationship, with the flat band gap parameter linearly increasing with the temperature above Tc ∼ 50 K. Thus, we find that either a magnetic or an electric field can drive this hydrogenated graphitic system to superconducting state below Tc ∼ 50 K. In addition, AF spin fluctuations creates pseudogap states above Tc ∼ 50 K.
Category: Condensed Matter