Can room-temperature data for tunneling molecular junctions be analyzed within a theoretical framework assuming zero temperature?

Abstract

Routinely, experiments on tunneling molecular junctions report values of conductances (GRT ) and currents (IRT ) measured at room temperature. On the other side, theoretical approaches based on simplified models...

Can tunneling current in molecular junctions be so strongly temperature dependent to challenge a hopping mechanism? Analytical formulas answer this question and provide important insight into large area junctions

“…To avoid possible confusions (see ref. 58 and 57), we reiterate that the presently defined Γ 's may differ by a factor of two from quantities denoted by the same symbol by other authors.…”

“…An important case of the low temperature limit is the offresonant transport, for which eqn (8a) acquires a particularly appealing form 43,57 I 0K…”

“…The rather minor difference between the value f = 4.9 Â 10 À4 based on eqn (12c) and the ''exact'' value f = 4.3 Â 10 À4 deduced via eqn (12a) is due to the fact, albeit smaller than |e 0 |, L is not smaller that |e 0 |/10, which is the condition for eqn (12c) to be very accurate. 57,58 7 Predicting a bias-tuned Sommerfeld-Arrhenius transition in a real molecular tunnel junction…”

“…, ref. 43, 52, 53 and 57) in terms of the geometric (“effective”) and arithmetic average ( Γ g and Γ a ) remain valid although a possible contribution of the surrounding environment to the MO width ( Γ env ) has not been explicitly mentioned. To avoid possible confusions (see ref.…”

“…Integration of eqn (4) can be carried out exactly and leads to the following formNoteworthily, eqn (7) is exact at arbitrary temperature T and bias V within the single level model with Lorentzian transmission. Limitations of this model have been discussed recently 57,61 and will not be repeated here. The above formula generalizes various particular results deduced for Γ env ≡ 0, 8,25,40,41,43,55,62–64 to which we will also refer below.…”