Longitudinal Photon Drag in p‐Type Tellurium

Abstract

The longitudinal photon drag has been studied for free holes in tellurium using a Q-switched CO, laser. A great effect is expected due to the great interband matrix element for allowed direct hole transitions between the sub-valence bands H, and H,. Due to the low crystal symmetry interesting anisotropy phenomena take place. The measurements have been performed for a set of samples, oriented either parallel or perpendicular to the c-axis. The drag effect connected with sub-band transitions is dominating as predicted by the theory (tensor coefficient ol13connected with the absorption of radiation polarized FW 1 c was found to be -1 x x 10-12cm/V a t 77 K.Der longitudinale photon-drag-Effekt an quasifreien Lochern in Tellur wird mit einem giitegeschalteten C0,-Laser untersucht. Wegen des groBen Interbandmatrixelements fur direkte erlaubte Locherubergange zwischen den Subvalenzbandern H, und H, ist ein groBer Effekt zu erwarten. Wegen der geringen Gittersymmetrie treten interessante Anisotropieeffekte auf. Die Messungen an einem Satz Proben, die entweder parallel oder senkrecht zur c-Achse des Tellurs orientiert waren, zeigen, daS erwartungsgemiS der mit den Subbandiibergangen verknupfte Effekt dominiert (Tensorkoeffizient ollS3 = 5 x 10-l2 cm/V bei T = 77 K). Der mit der Absorption von Strahlung PW c verkniipfte Koeffizient cXdl1 wiirde zu -1 x lo-'* cm/V bei 77 K bestimmt.

Theory of the photon‐drag effect in semiconductors with elliptical isoenergetic surfaces and its application to tellurium crystals

“…(Here and in the following a Cartesian coordinate system is chosen as follows: the z3 axis is parallel to the optical c-axis and the z1 axis is parallel to one of the electric axes.) I n tellurium the tensor cik:lm has ten independent coefficients [4]. Especially interesting are the coefficients a , = a,,, and am3, because they are related to direct allowed optical transitions between Up to now a complete theory of transport effects in tellurium, using the complex band structure and the k-dependence of the matrix elements for all electronic transitions, which is connected with the band non-parabolicity, does not exist.…”