The Effect of Pressure on Conductivity and Permittivity of As2Te3-Based Glasses

Abstract

based glasses the conductivity 0, due t o carriers excited to extended states near the mobility edge, strongly increases with increasing pressure. I n As,Te, 0 measured a t room temperature rises by a factor of = 50 a t a pressure of 1 GPa. I n contrast to u, the low-temperatdre frequency-dependent hopping conductivity up is nearly pressure independent. The change of u with pressure is a result of pressure-induced decrease in the mobility gap. The pressure independence of uF is discussed with respect to Elliott's theory for ac conductivity. The permittivity in these glasses increases by less than 25% at 1 GPa. The pressure increase in permittivity is given by a positive change of the electronic contribution and a smaller negative change of the atomic contribution to the static permittivity.Dans les semiconducteurs vitreux As,Te,Si, et As,Te,Tl, (oh x = 0; 0,3; 0,6 et l), la conductiviti: blectrique u, due aux porteurs excites aux btats &tendus prAs du bord de mobilitb, croit rapidement avec la pression. Par example, dans As,Te, u mesuree It la tempkrature ambiante augmente = 50-fois h, la pression de 1 GPa. A la diffbrence de u, la conductiviti: dkpendente de la frkquence UF est presque indkpendante de la pression. La variation de (T avec la pression est attribuek It la diminution de la bande interdite SOUS la pression. Une variation faible de oF avec la pression est discutke par rapport It la th6orie de la conduction par saut par Elliott. La permittivitk des verres btudiks augmente par moins de 25% It 1 GPa. L'accroissement de la permittivitb sous la pression est dii it une variation positive de la contribution electronique et ti une variation negative plus lente de la contribution atomique la permittivitb.

Theoretical prediction of the structural, electronic, mechanical and thermodynamic properties of the binary α-As 2 Te 3 and β-As 2 Te 3

“…(5) The 3D directional dependences of the reciprocal of Young's modulus and bulk modulus for α and β phase are obtained. Base on our calculated, we can conclude that the α phase exhibits remarkable anisotropy (6). In addition, the Debye temperature and thermal conductivity of β phase larger than that of α phase.…”

“…The first chalcogenide glasses to show these effects are in the As-Te-I system [2]. One of the most interesting binary chalcogenide glasses is As 2 Te 3 [3][4][5][6]. The As 2 Te 3 exhibits electrical threshold and memory switching, and have been used in thermoelectric refrigeration and memory devices [7][8][9][10][11][12].…”

Structural, Vibrational, and Electronic Study of α-As2Te3 under Compression

“…While there is still no experimental result on β-As 2 Te 3 under pressure, a recent work has reported electrical measurements at HP combined with theoretical ab initio calculations and observed the metallization of α-As 2 Te 3 above 5 GPa; however, another recent work has suggested on the basis of theoretical calculations that there is no metallization of α-As 2 Te 3 on increasing pressure but there are two second-order electronic transitions . These recent studies contrast with previous studies of amorphous and liquid semiconductors As 2 S 3 , As 2 Se 3 , and As 2 Te 3 at HP that suggested a decrease of the optical and electronic bandgap with increasing pressure, leading to a common semiconductor–metal transition and glass transitions. − …”

As2Te3 glass under high hydrostatic pressure: Polyamorphism, relaxation, and metallization

“…The electrical resistivity of the bulk glasses g-As 2 Te 3 was studied at a pressure up to 6.5 GPa [22]. All studies of the electrical resistivity of compressed a-As 2 Te 3 and g-As 2 Te 3 were performed under nonhydrostatic conditions excluding moderate pressures up to 1 GPa [23]. It is interesting that g-As 2 Te 3 is an example of a few glasses whose vitrification and crystallization temperatures decrease rapidly (at a rate of 2−3 K/kbar) with an increase in the pressure [24].…”