Figure 2 .

Modification of the BN bandgap.(a) The gap enhancement depends mainly on λ , is weakly dependent on Δ and shows almost no change with Ω. Calculations are made for Δ =t corresponding to a BN gap of 2Δ =4.66 eV, Δ =1.20t (2Δ =5.6 eV), and Δ =0.84t (2Δ =3.92 eV, the tight binding fit from reference [10]). t =2.33 eV, <a onClick="popup('http://www.nanoscalereslett.com/content/7/1/303/mathml/M18','MathML',630,470);return false;" target="_blank" href="http://www.nanoscalereslett.com/content/7/1/303/mathml/M18">View MathML</a> meV, <a onClick="popup('http://www.nanoscalereslett.com/content/7/1/303/mathml/M19','MathML',630,470);return false;" target="_blank" href="http://www.nanoscalereslett.com/content/7/1/303/mathml/M19">View MathML</a> meV, <a onClick="popup('http://www.nanoscalereslett.com/content/7/1/303/mathml/M20','MathML',630,470);return false;" target="_blank" href="http://www.nanoscalereslett.com/content/7/1/303/mathml/M20">View MathML</a> meV, <a onClick="popup('http://www.nanoscalereslett.com/content/7/1/303/mathml/M21','MathML',630,470);return false;" target="_blank" href="http://www.nanoscalereslett.com/content/7/1/303/mathml/M21">View MathML</a> meV, covering the full range of phonon frequencies in reference [13]. k B T =0.01t (T =268K) and λ ≤1. (b) Variation of the gap with temperature, <a onClick="popup('http://www.nanoscalereslett.com/content/7/1/303/mathml/M22','MathML',630,470);return false;" target="_blank" href="http://www.nanoscalereslett.com/content/7/1/303/mathml/M22">View MathML</a> meV and λ =0.2. There is a weak temperature dependence due to the large Δ, consistent with the measurements in reference [15], with gap starting to close only for extremely high temperatures T >8,000 K , presumably above the melting point of the material. Red circles show the size of the gap, red lines are a guide to the eye.

Hague Nanoscale Research Letters 2012 7:303   doi:10.1186/1556-276X-7-303
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