Field-induced low-temperature electronic specific heat of boron nitride nanotubes

TL;DR

This study investigates how a transverse electric field influences the low-temperature electronic specific heat of boron nitride nanotubes, revealing significant modulation, peak structures at critical fields, and geometry-dependent effects.

Contribution

It demonstrates the electric field's ability to significantly alter the electronic specific heat and identifies the role of nanotube geometry and magnetic flux in this modulation.

Findings

Electric field causes peak structures in density of states at critical field.

Giant specific heat appears at critical electric field, comparable to phonon specific heat.

Magnetic flux enhances specific heat in ZBNNTs at low temperature.

Abstract

We use the tight-binding model to study the effect of transverse electric field on the low-temperature electronic specific heat (Cv) for armchair and zigzag boron nitride nanotubes (ABNNTs and ZBNNTs). For wide-band-gap BNNTs, electric field could significantly modulate their energy dispersions and shift many electronic states close to the Fermi energy. Under a critical electric field (Fc) the density of states show special peak structures and the vanishing specific heat at zero field jumps to a giant one. Cv, at Fc's, has a value comparable to that of the phonon specific heat and reveals strongly non-linear dependence on temperature. The critical field strength and the value of giant specific heat are closely related to nanotube's geometry. In the presence of Fc's, the extra longitudinal magnetic flux could enhance the value of Cv again at low temperature for ZBNNTs, whereas it is not always true for ABNNTs.