Theoretical estimation of dielectric loss of oxide glasses using nonequilibrium molecular dynamics simulations

Abstract

To theoretically explore amorphous materials with a sufficiently low dielectric loss, which are essential for next-generation communication devices, the applicability of a nonequilibrium molecular dynamics simulation employing an external alternating electric field was examined using alkaline silicate glass models.In this method, the dielectric loss is directly evaluated as the phase shift of the dipole moment from the applied electric field. This method enabled us to evaluate the dielectric loss in a wide frequency range from 1 GHz to 10 THz. It was observed that the dielectric loss reaches its maximum at a few THz. The simulation method was found to qualitatively reproduce the effects of alkaline content and alkaline type on the dielectric loss. Furthermore, it reasonably reproduced the effect of mixed alkalines on the dielectric loss, which was observed in our experiments on sodium and/or potassium silicate glasses. Alkaline mixing was thus found to reduce the dielectric loss.

Dielectric property and polarization mechanism of sodium silicate glass in GHz–THz range

“…The polarizations induced by the AC electric field were determined by following the method proposed in Ref. 39. The number of atoms in the glass models was approximately 5000.…”

“…The slab model was kept at 500 K for 300 ps to relax the atomic positions near the boundary. Note that the MD simulations were performed at 500 K instead of 300 K, which was temperature of experimental condition, because the previous work 39) confirmed the dielectric loss attributed to ion dynamics is more clearly observed at 500 K rather than 300 K.…”

Development of a force field for modeling lithium borosilicate glasses

“…Indeed, the CMD simulations have been applied to measure the ion conductivity of glass materials. For instance, the mechanisms of alkaline mixing effect on alkaline ion conductivity [18][19][20][21][22][23] and dielectric loss relating to the delay of atom motion compared with an applied electric field 24 were successfully unraveled. However, the CMD simulation study on LBS glass is very limited due to the lack of an accurate force field (FF).…”

“…Because the PMMCS 26 and Teter potentials 27 cover a wide range of compositions, they have been well examined to study glass structures, mechanical properties, 28 and ion dynamics. 23,24 The Sundararaman-Huang-Ispas-Kob (SHIK) potential was developed based on 𝑎𝑏 𝑖𝑛𝑖𝑡𝑖𝑜 calculation results of local structure in melting condition, as well as experimental Young's modulus and density. 29,30 The SHIK potential was extended to simulate alkalinecontaining borate glasses by considering boron coordination in the cost function to optimize the parameter set.…”

“…Many efforts have already been devoted to developing reliable FFs for modeling oxide glasses using MD simulations. Because the PMMCS 26 and Teter potentials 27 cover a wide range of compositions, they have been well examined to study glass structures, mechanical properties, 28 and ion dynamics 23,24 . The Sundararaman‐Huang‐Ispas‐Kob (SHIK) potential was developed based on $$ab$$ $$initio$$ calculation results of local structure in melting condition, as well as experimental Young's modulus and density 29,30 .…”