Ballistic and shift currents in the bulk photovoltaic effect theory
B.I. Sturman Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, prosp. akad. Koptyuga 1, Novosibirsk, 630090, Russian Federation
The bulk photovoltaic effect (BPVE) — the generation of electric currents by light in noncentrosymmetric materials in the absence of electric fields and gradients — was intensively investigated at the end of the last century. The outcomes, including all main aspects of this phenomenon, were summarized in reviews and books. A new upsurge of interest in the BPVE has occurred recently, resulting in a flood of misleading theoretical and experimental publications centered around the so-called shift current. Numerous top-rated recent publications ignore the basic principles of charge-transport phenomena and the previous results of joint experimental-theoretical studies. Specifically, dominating (or substantial) contributions to currents caused by asymmetry of the momentum distributions of electrons and holes are missed. The wide-spread basis relation for the shift current ignores the kinetic processes of relaxation and recombination of photo-excited electrons and leads to non-vanishing shift currents in thermal equilibrium. The goals of this methodical note is to specify and argue the benchmarks of the BPVE theory and return studies to the right track in the interest of developing photovoltaic devices.
Keywords: media without central symmetry, bulk photovoltaic effect, polarization properties, ballistic currents, shift currents, kinetic processes, photoexcitation asymmetry PACS:03.65.−w, 72.10.Bg, 72.10.−d, 72.40.+w, 73.50.Gr (all) DOI:10.3367/UFNe.2019.06.038578 URL: https://ufn.ru/en/articles/2020/4/g/ Citation: Sturman B I "Ballistic and shift currents in the bulk photovoltaic effect theory" Phys. Usp.63 407–411 (2020)