Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides

Details Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides

2010-01-29

arxiv.org/abs/1001.5458v1

Phys. Rev. B 81, 144114 (2010)

Physics

Condensed Matter

Materials Science

PDF only

Scientific paper

10.1103/PhysRevB.81.144114

Electronic structure and lattice dynamics calculations on thallium halides show that the Born effective charges in these compounds are more than twice larger than the nominal ionic charges. This is a result of cross-band-gap hybridization between Tl-p and halogen-p states. The large Born charges cause giant splitting between longitudinal and transverse optic phonon modes, bringing the lattice close to ferroelectric instability. Our calculations indeed show spontaneous lattice polarization upon lattice expansion starting at 2%. It is remarkable that the apparently ionic thallium halides with a simple cubic CsCl structure and large differences in electronegativity between cations and anions can be very close to ferroelectricity. This can lead to effective screening of defects and impurities that would otherwise be strong carrier traps and may therefore contribute to the relatively good carrier transport properties in TlBr radiation detectors.

Affiliated with

Also associated with

No associations

Rating

Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhanced Born Charge and Proximity to Ferroelectricity in Thallium Halides will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-677139