Ake v. Oklahoma held that "when a defendant demonstrates to the trial judge that his sanity at the time of the offense is to be a significant factor at trial, the State must, at a minimum, assure the defendant access to a competent psychiatrist who will conduct an appropriate examination and assist in evaluation, preparation, and presentation of the defense." 470 U.S. at 83. The court of criminal appeals has extended the reasoning in Ake to cases involving various types of experts. See, e.g., Rey v. State, 897 S.W.2d 333 (Tex. Crim. App. 1995) (pathologist in capital murder case); McBride v. State, 838 S.W.2d 248 (Tex. Crim. App. 1992) (chemist in controlled substance case). The court has indicated that the defendant must make a "preliminary showing of a significant issue of fact on which the State would present expert testimony, and which the knowledge of a lay jury would not be expected to encompass." Jackson v. State, 992 S.W.2d 469, 474 (Tex. Crim. App. 1999). "The appointment of an expert witness under Art. 26.05 . . . rests within the sound discretion of the trial court." Stoker v. State, 788 S.W.2d 1, 16 (Tex. Crim. App. 1989); see also De Freece v. State, 848 S.W.2d 150, 161 (Tex. Crim. App. 1993) (any failure to appoint expert under article 26.05 is subject to abuse of discretion standard). We may reverse the trial court's decision for an abuse of discretion only when it appears that the court applied an erroneous legal standard, or when no reasonable view of the record could support the trial court's conclusion under the correct law and the facts viewed in the light most favorable to its legal conclusion. See Dubose v. State, 915 S.W.2d 493, 497-98 (Tex. Crim. App. 1996). Even if we would have reached a different result, we should not intercede as long as the trial court's ruling was within the "zone of reasonable disagreement." Montgomery v. State, 810 S.W.2d 372, 391 (Tex. Crim. App. 1991).