Condensed Matter

2202 Submissions

[4] viXra:2202.0157 [pdf] submitted on 2022-02-24 19:38:13

Ekagi-Dutch-English-Indonesian Dictionary by J. Steltenpool and the Onsager's Solution

Authors: Anindya Kumar Biswas
Comments: 18 Pages.

We consult Ekagi-Dutch-English-Indonesian Dictionary by J. Steltenpool. Here we count all the Ekagi head words initiating with a letter. We draw the natural logarithm of the number of words, normalised, starting with a letter vs the natural logarithm of the rank of the letter. We find that the words underlie a magnetisation curve. The magnetisation curve i.e. the graph of the reduced magnetisation vs the reduced temperature is the exact Onsager solution of the two dimensional Ising model in the absence of external magnetic field.
Category: Condensed Matter

[3] viXra:2202.0155 [pdf] submitted on 2022-02-24 19:47:16

Quantum Effects in Graphitic Materials: Colossal Magnetoresistance, Andreev Reflections, Ferromagnetism, and Granular Superconductivity

Authors: Nadina Gheorghiu, Charles R. Ebbing, Benjamin T. Pierce, Timothy J. Haugan
Comments: 9 Pages. [Corrections are made by viXra Admin to comply with the rules of viXra.org]

Unlike the more common local conductance spectroscopy, nonlocal conductance can differentiate between nontopological zero-energy modes localized around inhomogeneities, and true Majorana edge modes in the topological phase. In particular, negative nonlocal conductance is dominated by the crossed Andreev reflection. Fundamentally, the effect reflects the system’s topology. In graphene, the Andreev reflection and the inter-band Klein tunneling couple electronlike and hole-like states through the action of either a superconducting pair potential or an electrostatic potential. We are here probing quantum phenomena in modified graphitic samples. Four-point contact transport measurements at cryogenic to room temperatures were conducted using a Quantum Design Physical Property Measurement System. The observed negative nonlocal differential conductance Gdiff probes the Andreev reflection at the walls of the superconducting grains coupled by Josephson effect through the semiconducting matrix. In addition, Gdiff shows the butterfly shape that is characteristic to resistive random-access memory devices. In a magnetic field, the Andreev reflection counters the effect of the otherwise lowered conduction. At low temperatures, the magnetoresistance shows irreversible yet strong giant oscillations that are known to be quantum in nature. In addition, we have found evidence for seemingly granular superconductivity. Thus, graphitic materials show potential for quantum electronics applications, including rectification and topological states.
Category: Condensed Matter

[2] viXra:2202.0140 [pdf] submitted on 2022-02-20 22:49:56

Update on the Method Using Nonlocal/noncontact Differential Conductance Experimental Data for Direct Probing Andreev Reflections and for Extracting the Superconducting Gap

Authors: Nadina Gheorghiu
Comments: 9 Pages.

In our previous work, high-temperature superconductivity (HTSC) was probed for the first time by using electrical differential conductance Gdiff(V) = dI/dV data as obtained from current-voltage V(I) measurements on a hydrogenated graphitic fiber [1]. While our nonlocal method for finding the superconducting (SC) gap was recently applied to a conventional SC (Pb [2]), the nonlocal Gdiff method was first proposed in [1]. Herein, we are bringing forth an update on the topic.
Category: Condensed Matter

[1] viXra:2202.0103 [pdf] submitted on 2022-02-15 20:02:40

A Method for Thermoelectric Figure of Merit Reaching 100 or Higher

Authors: Yuanjie Huang
Comments: 18 Pages.

Since several decades, many efforts have been made all over the world to achieve the highly efficient conversion from low-grade thermal energy into electrical energy and the conversion efficiency is usually described by Thermoelectric Figure of Merit, i.e., ZT coefficient. However, the highest ZT coefficient have not reached 4 in spite of worldwide scientific researches for many years. In this work, a method for reaching an unprecedented ZT coefficient was proposed by utilizing phase-transition induced sudden change of electric potential for the oxidation-reduction couple at an electrode material in a thermogalvanic cell (TGCs). It was found that such TGCs could exhibit ZT coefficient of the order 100 and even higher, and this new type of thermogalvanic cell was named phase-transition thermogalvanic cell (PT-TGCs). By optimizing the experimental design, the PT-TGCs may convert waste heat into electrical power more effectively and would be applied in various areas in the future.
Category: Condensed Matter