Maximum efficient of quantum thermoelectrics at finite power output

by Robert S. Whitney

at Physics Colloquium

Thu, 29 Oct 2015, 15:30
Physics building (#54) room 207

Abstract

Machines are only Carnot efficient if they are reversible but then their power output is vanishingly small Here we ask what is the maximum efficiency of an irreversible device with finite power output It turns out that classical thermodynamics is insufficient to answer this rather simple question we need quantum mechanics In this colloquium we introduce the bulk thermoelectrics that are currently used for power generation and refrigeration We then turn to quantum thermoelectric effects Seebeck and Peltier effects in nanostructures or molecules We consider the thermodynamics of a simple model of such a quantum thermoelectric a nonlinear scattering theory We find that quantum mechanics places an upper bound on both power output and on the efficiency at any finite power The upper bound on efficiency equals Carnot efficiency at zero power output but decays with increasing power output It is intrinsically quantum wavelength dependent unlike Carnot efficiency A physical implementation which could achieve the upper bound will be discussed as will the suppression of efficiency by a phonon heat flow References : R S Whitney Phys Rev Lett 112 130601 2014 Phys Rev B 91 115425 2015 Refreshments are served at 3:20pm

Created on 07-10-2015 by Bar Lev, Yevgeny (ybarlev)
Updaded on 07-10-2015 by Bar Lev, Yevgeny (ybarlev)