Diamagnetic currents in the closed-shell electronic structures in sp3-type hydrocarbons

The mechanism of the occurrence of diamagnetic currents in sp3-type electronic states in alkanes and pure diamonds is suggested, from analogy with the nondissipative diamagnetic currents in closed-shell electronic structures in aromatic hydrocarbons such as polyacenes and annulenes with microscopic sizes. It is found that most of all electrons can form electron pairs originating from attractive Coulomb interactions between two electrons with opposite momenta and spins occupying the same orbitals in pure diamonds with macroscopic sizes at 298 K. In principle, diamagnetic currents in alkanes and pure diamonds can be expected to occur by such electron pairing. The diamagnetic conducting transition temperature TcneutralNsp3 values for macroscopic sized diamonds with large valence-conduction band gaps are estimated to be much larger than the superconducting transition temperatures Tc,BCS values for the conventional superconductors with small valence-conduction band gaps. Even very small ratio of impurities or dopants would destroy possible nondissipative diamagnetic current states in the diamonds with macroscopic sizes. Therefore, very pure diamonds exhibiting nondissipative diamagnetic currents are very difficult to be produced up to now, and diamonds with impurities would become insulator or semiconductor. The technology which enables us to produce very pure diamonds in which no impurities exist is awaited to investigate whether such pure diamonds become nondissipative diamagnetic current states or not at 298 K.