Anomalous beating phase of the oscillating interlayer magnetoresistance in layered metals

We analyze the beating behavior of the magnetic quantum oscillations in a layered metal under the conditions when the cyclotron energy (h) over bar omega(c) is comparable to the interlayer transfer energy t. Using a simple semi-classical model, we show that the positions-of the beats in the interlayer resistance are considerably shifted from those in the magnetization oscillations. The shift is determined by the ratio (h) over bar omega(c)/t that may lead to significant deviations from the conventional periodicity of the beats in the scale of inverse magnetic field. A comparative study of the Shubnikov-de Haas and de Haas-van Alphen oscillations in the layered organic metal beta-(BEDT-TTF)(2)IBr2 is performed and shown to be consistent with the theoretical prediction.