4 research outputs found
Wiedemann-Franz law in a non-Fermi liquid and Majorana central charge: Thermoelectric transport in a two-channel Kondo system
Quantum dot devices allow one to access the critical point of the two-channel
Kondo model. The effective critical theory involves a free Majorana fermion
quasiparticle localized on the dot. As a consequence, this critical point shows
both the phenomenon of non-Fermi liquid physics and fractionalization. Although
a violation of the Wiedemann-Franz law is considered a defining feature of
non-Fermi liquid systems, we show by exact calculations that it holds at the
critical point, providing a counterexample to this lore. Furthermore, we show
that the fractionalized Majorana character of the critical point can be
unambiguously detected from the heat conductivity, opening the door to a direct
experimental measurement of the elusive Majorana central charge
.Comment: 18 pages, 3 figure
Engineering of Chern insulators and circuits of topological edge states
Impurities embedded in electronic systems induce bound states which under
certain circumstances can hybridize and lead to impurity bands. Doping of
insulators with impurities has been identified as a promising route towards
engineering electronic topological states of matter. In this paper we show how
to realize tuneable Chern insulators starting from a three dimensional
topological insulator whose surface is gapped and intentionally doped with
magnetic impurities. The main advantage of the protocol is that it is robust,
and in particular not very sensitive to the impurity configuration. We
explicitly demonstrate this for a square lattice of impurities as well as a
random lattice. In both cases we show that it is possible to change the Chern
number of the system by one through manipulating its topological state. We also
discuss how this can be used to engineer circuits of edge channels.Comment: 9 pages, 6 figure
Wiedemann-Franz law in a non-Fermi liquid and Majorana central charge: Thermoelectric transport in a two-channel Kondo system
Quantum dot devices allow one to access the critical point of the two-channel Kondo model. The effective critical theory involves a free Majorana fermion quasiparticle localized on the dot. As a consequence, this critical point shows both the phenomenon of non-Fermi-liquid physics and fractionalization. Although a violation of the Wiedemann-Franz law is often considered to be a sign of non-Fermi-liquid systems, we show by exact calculations that it holds at the critical point, thereby providing a counterexample to this lore. Furthermore, we show that the fractionalized Majorana character of the critical point can be unambiguously detected from the heat conductance, opening the door to a direct experimental measurement of the elusive Majorana central charge c = 1 2
Wiedemann-Franz law in a non-Fermi liquid and Majorana central charge: Thermoelectric transport in a two-channel Kondo system
Quantum dot devices allow one to access the critical point of the two-channel Kondo model. The effective critical theory involves a free Majorana fermion quasiparticle localized on the dot. As a consequence, this critical point shows both the phenomenon of non-Fermi-liquid physics and fractionalization. Although a violation of the Wiedemann-Franz law is often considered to be a sign of non-Fermi-liquid systems, we show by exact calculations that it holds at the critical point, thereby providing a counterexample to this lore. Furthermore, we show that the fractionalized Majorana character of the critical point can be unambiguously detected from the heat conductance, opening the door to a direct experimental measurement of the elusive Majorana central charge c = 1 2