Temperature Dependence of Charge and Spin Transfer in Azurin

Abstract

The steady-state charge and spin transfer yields were measured for three different Ru-modified azurin derivatives in protein films on silver electrodes. While the charge-transfer yields exhibit weak temperature dependences, consistent with operation of a near activation-less mechanism, the spin selectivity of the electron transfer improves as temperature increases. This enhancement of spin selectivity with temperature is explained by a vibrationally induced spin exchange interaction between the Cu(II) and its chiral ligands. These results indicate that distinct mechanisms control charge and spin transfer within proteins. As with electron charge transfer, proteins deliver polarized electron spins with a yield that depends on the protein’s structure. This finding suggests a new role for protein structure in biochemical redox processes.

A Chirality-Based Quantum Leap

“…(e) Model of vibronically activated spin-polarization. Adapted with permission from ref ( 64 ). Copyright 2021 American Chemical Society.…”

Common Trends of Chiral Induced Spin Selectivity and Optical Dichroism with Varying Helix Pitch: A First-Principles Study

“…It is well known that the polarizability is related to the optical activity [79,80,67,10,6]. Accordingly, as a more indirect rationalization, we have calculated the isotropic and anisotropic polarizabilities (Eqs.…”

The Chiral Induced Spin Selectivity Effect -- What It Is, What It Is Not, And Why It Matters

“…The chiral induced spin selectivity effect has been reproducibly observed in various measurements, for instance, light exposure [1,2,[4][5][6][7][8][9][10], local probing techniques [11][12][13][14][15], transport [12,16,17] and different types of Hall measurements [5,6,[18][19][20]. However, although all measurements entail non-equilibrium conditions, with only a few exceptions, essentially all theoretical accounts of the effect are based on the transmission properties of chiral molecules embedded in a given environment, see for instance Refs.…”

“…The transport set-ups, in which the charge current is under scrutiny, are intuitive in the sense that there is, at least, one electrode which can be magnetized in different directions, see Figure 1, which thereby enables a control of the external magnetic conditions. Theoretical models to address the * Jonas.Fransson@physics.uu.se measured currents under such conditions have been proposed [9,[49][50][51][52][53][54][55][56][57][58], where essentially all these various models comprise a coupling between the electronic degrees of freedom to some other, both Fermionic [50,51,55,58] and Bosonic [9, 52-54, 56, 57], degrees of freedom. Also in the photospectroscopy experiments, a magnetic metal is often coupled to the sample [9] and, hence, provide a control of the magnetic conditions in a similar way.…”

“…Theoretical models to address the * Jonas.Fransson@physics.uu.se measured currents under such conditions have been proposed [9,[49][50][51][52][53][54][55][56][57][58], where essentially all these various models comprise a coupling between the electronic degrees of freedom to some other, both Fermionic [50,51,55,58] and Bosonic [9, 52-54, 56, 57], degrees of freedom. Also in the photospectroscopy experiments, a magnetic metal is often coupled to the sample [9] and, hence, provide a control of the magnetic conditions in a similar way. The magnetic response can also be controlled using circularly polarized light [1,2].…”