A mechanical beam resonator engineered at nanoscale for suppressing thermoelastic damping to obtain ultrahigh quality factor is reported. The resonator employs the torsion mode of a spring beam to excite the rotation oscillation of a nanoscale resonant beam. The ultralow thermoelastic damping in the resonator is obtained by employing torsion oscillation. Optimal study of thermoelastic damping is carried out by varying the dimensional parameters of the resonator. The resonator operating in the MHz regime with the quality factor over one million is obtainable by the proposed oscillation exciting method and appropriate design of dimensional parameters of the beams. In order to obtain such overall intrinsic quality factor, virtual supports are employed to eliminate attachment loss in the resonator.
